Wet-coating of thin film lithium nickel oxides for electrochromic applications

ABSTRACT

Process for forming a multi-layer electrochromic structure, the process comprising depositing a film of a liquid mixture onto a surface of a substrate, and treating the deposited film to form an anodic electrochromic layer, the liquid mixture comprising a continuous phase and a dispersed phase, the dispersed phase comprising metal oxide particles, metal hydroxide particles, metal alkoxide particles, metal alkoxide oligomers, gels or particles, or a combination thereof having a number average size of at least 5 nm.

The present disclosure generally relates to liquid compositionscomprising lithium nickel oxides, methods for preparing lithium nickeloxide compositions adapted for thin film deposition onto a substrate forthe formation of switchable electrochromic multi-layer devices, andmethods for preparing multi-layer structures comprising such films.

Commercial switchable glazing devices, also commonly known as smartwindows and electrochromic window devices, are well known for use asmirrors in motor vehicles, aircraft window assemblies, sunroofs,skylights, and architectural windows. Such devices may comprise, forexample, active inorganic electrochromic layers, organic electrochromiclayers, inorganic ion-conducting layers, organic ion-conducting layersand hybrids of these sandwiched between two conducting layers. When avoltage is applied across these conducting layers the optical propertiesof a layer or layers in between change. Such optical property changestypically include a modulation of the transmissivity of the visible orthe solar sub-portion of the electromagnetic spectrum. For convenience,the two optical states will be referred to as a bleached state and adarkened state in the present disclosure, but it should be understoodthat these are merely examples and relative terms (i.e., a first one ofthe two states is more transmissive or “more bleached” than the otherstate and the other of the two states is less transmissive or “moredarkened” than the first state) and that there could be a set ofbleached and darkened states between the most transmissive state and theleast transmissive state that are attainable for a specificelectrochromic device; for example, it is feasible to switch betweenintermediate bleached and darkened states in such a set.

The broad adoption of electrochromic window devices in the constructionand automotive industries will require a ready supply of low cost,aesthetically appealing, durable products in large area formats.Electrochromic window devices based on metal oxides represent the mostpromising technology for these needs. Typically, such devices comprisetwo electrochromic materials (a cathode and an anode) separated by anion-conducting film and sandwiched between two transparent conductingoxide (TCO) layers. In operation, a voltage is applied across the devicethat causes current to flow in the external circuit, oxidation andreduction of the electrode materials and, to maintain charge balance,mobile cations to enter or leave the electrodes. This facileelectrochemical process causes the window to reversibly change from amore bleached (e.g., a relatively greater optical transmissivity) to amore darkened state (e.g., a relatively lesser optical transmissivity).

For long-term operation of an electrochromic window, the componentswithin the device must be well matched; e.g., the electrochemicalpotentials of the electrodes over their states of charge should bewithin the voltage stability window of the ion conductor and of the TCOmaterial. If not, electron transfer will occur between the electrodematerials and the other window components causing, for example, leakagecurrent, electrolyte consumption, buildup up of reaction products on theelectrode(s) and, in general, significantly shortening the usefullifespan of the window.

TCO materials typically used in electrochromic windows such as FTO andITO react with lithium at voltages below ˜1V vs. Li/Li⁺, lowering theirelectrical performance and darkening the material. Electrolytestypically incorporated into the ion conductor, or the presence of wateror protic impurities, have voltage stability windows between ˜1 and ˜4.5V vs. Li/Li⁺. Therefore, it is beneficial to use electrode materialsthat undergo redox events within these limits. For example, tungstenoxide (WO₃) is a well-known cathodic electrochromic material that isbleached at ˜3.2 V vs. Li/Li⁺ and darkens upon reduction, typically to˜2.3 V vs. Li/Li⁺. Consequently, electrochromic devices comprising atungsten oxide cathode are common.

Certain nickel oxide and hydroxide based materials darken anodically toproduce a darkened state transmission spectrum that is complementary tolithiated WO₃ and it is a popular target to partner WO₃ inelectrochromic windows. Certain methods for the preparation of lithiumnickel oxide films (LiNiO_(x)) have been reported in the literature.These include sputter methods (see, e.g., Rubin et. al. Solar EnergyMaterials and Solar Cells 54; 998 59-66) and solution methods (see,e.g., Svegl et. al., Solar Energy V 68, 6, 523-540, 2000). In both casesthe films exhibit high area charge capacity (>20 mC/cm²), with bleachedstate voltages of ˜1-1.5V. This bleached state voltage is relativelyclose to the reaction potential of lithium with typical TCO materials,the lower voltage limit of common electrolytes and the reactionpotential required to over-reduce lithiated nickel oxides to nickelmetal, a cathodic electrochromic reaction. The proximity of the bleachedstate voltage to such degrading mechanisms presents significant devicecontrol issues: methods will be required to consistently drive thedevice to the bleached state without driving the anode into damagingvoltage regimes accommodating, for example, issues such as localelectrode inhomogeneity. Furthermore, the bleached state lithiatednickel oxide cannot typically be handled in air without the materialperformance degrading. For example, U.S. Pat. No. 6,859,297 B2 describesthe lithiation (and bleaching) of nickel oxide films that requiredhandling in a controlled atmosphere to preclude their exposure to waterand oxygen.

A wide variety of film deposition processes have been described forproducing metal oxide anode and cathode materials for electrochromicdevices including vapor deposition (e.g., sputtering, CVD) and wetchemical methods (dip coating, spin coating). Each of these methodsrequires optimization of the film composition and film depositionprocessing so that high quality films (e.g., crack-free, uniform filmson large area substrates having strong adhesion and electrical contactwith the transparent conducting and ion-conducting interfaces) arecreated in “Electrochemically and Optically Matched” states (EOM). Ingeneral, cathode and anode films are in an EOM state when their chargecapacities are similar, they are in their complementary optical states(e.g., both in their clear states) and electrochemical states (e.g., onereduced the other oxidized) and one film colors cathodically while theother film colors anodically.

Regarding wet chemical deposition processes, solution-based methods arewidely used for the synthesis of inorganic materials. Under certainconditions, wet chemical processes can be particularly optimized for thepreparation of thin films on various substrates. Depending on theapplication, different types of liquid deposition techniques, forexample, dip-coating, spin coating or the like, may necessitatedifferent solution optimizations even for the same target compositions.Liquid mixtures such as those utilized in sol-gel processes areparticularly interesting because of the breadth of chemicalmodifications that are possible.

Sol-gel processing, initially for the preparation of silica, has beenknown generally since the 1930s although gelation phenomena wereobserved upon the exposure of SiCl₄ in alcohol to ambient atmospheresince the mid-19th century. Development continued, exploding around the1980s. Sol-gel processing, in a variety of forms, is commonly used forthe preparation of bulk powders, films, fibers, or monoliths. Althoughthe majority of research and technical reports remain concentrated inthe examination of a small group of metals (e.g., Si, Al, Ti, V andseveral others), broad use is extremely common especially in academicgroups.

Attractive features of the methodology include the use of liquidprecursors to facilitate homogenous mixing. These materials are easilymodified using conventional chemical syntheses and methods. Solutionviscosities are easily optimized and reaction temperatures are oftenreduced as compared to conventional preparative techniques.

Broadly, the sol-gel process involves the formation of a hydroxy and/oroxo network through hydroxylation and condensation reactions of amolecular precursor, often a metal alkoxide. A sol is a stabledispersion of large molecules or small particles. A gel is a 3-D networkthat captures a liquid phase (solvent). Depending on the final productform, different methods are known, for example, to remove solvent,decompose additives, draw fibers, cast films and/or generate particles.Both aqueous and non-aqueous routes are well known. Certain molecularcomplexes are favored for certain purposes but should not be viewed aslimiting in a general sense. Additives specific to certain chemistriesare common, as are additives specific to the form of the finalproduct—these also are not limiting. As an example, anti-cracking agentsthat are common for the preparation of a film may be unnecessary if thefinal product is a powder.

Although a wide variety of precursors for sol-gel processes exist, metalalkoxides are probably the most popular. One reason for their popularityis that alkoxides react readily with water. This reaction is calledhydrolysis because a hydroxyl ion becomes attached to the metal center(M) as shown in the following reaction:M(OR)_(x)+H₂O→HO—M(OR)_(x-1)+ROH  (1)

In this reaction, the R can represent a proton or another ligand (forexample if R is an alkyl group, then •OR is an alkoxy group and ROH isan alcohol). Depending on the quantity of water added and whether acatalyst is present, hydrolysis may go to completion, i.e. all of the ORgroups are replaced by OH, e.g. M(OH)_(x) as shown in reaction (2):M(OR)_(x) +xH₂O→M(OH)_(x) +xROH  (2)Alternatively, if hydrolysis does not proceed to completion, the metal(M) is only partially hydrolyzed, e.g. M(OR)_(x-y)(OH)_(y). Twopartially hydrolyzed metals can react together in a condensationreaction as shown in reactions (3) and (4):(OR)_(x)M—OH+HO—M(OR)_(x)→(OR)_(x)M-O—M(OR)_(x)+H₂O  (3)or(OR)_(x)M—OR+HO—M(OR)_(x)→(OR)_(x)M-O—M(OR)_(x)+ROH  (4)Thus, by definition, condensation reactions will liberate either wateror alcohol. In this regard, the reactions can be self-propagating to acertain extent. Under certain conditions, however, condensation may belimited. For example, if the metal complex M(OR)_(x) is modified toML(OR)_(x-1), where L is an unreactive ligand, fewer condensationreactions will be possible per metal center. The nature of thischemistry is highly complex and is described in more detail in Sol-GelScience: The Physics and Chemistry of Sol-Gel Processing, by C. JeffreyBrinker and George W. Scherer.

Many crystal lattices may be described using the idea of close packingof spheres. Assuming that these spheres represent anions, a wide rangeof structures derive from metal (cation) occupation of the octahedraland tetrahedral sites within close packed anion arrays. In such arrays,there are equal numbers of octahedral sites as anions and twice as manytetrahedral sites as anions. The term “rock salt” as used hereindescribes a cubic structure in which metal cations (“M”) occupy all ofthe octahedral sites within a close packed anion array, resulting in thestoichiometry MO. Furthermore, the metals are indistinguishable from oneanother regardless of whether the metals are the same element or arandom distribution of different elements. In the specific case of NiO,for example, the cubic rock salt unit cell is ˜4.2 Å on a side and byX-ray diffraction, the largest d-spacing is ˜2.4 Å. In the case wherethere is more than one type of metal, different analogues of the rocksalt parent structure may be created depending upon how and if themetals order themselves over the octahedral and tetrahedral sites. Thecase of Li_(x)Ni_(1-x)O is instructive: for all values of x, the oxygenanions are close packed and the metals are arranged on the octahedralsites. For values of x less than ˜0.3, the lithium and nickel cationsare randomly arranged; for values of x greater than 0.3, the metalssegregate to create nickel-rich and lithium-rich layers, resulting in alayered structure and a reduction to hexagonal symmetry from cubic. Theend member, Li_(1/2)Ni_(1/2)O (equivalently, LiNiO₂) is formed fromalternate layers of —Ni—O—Li—O— with a hexagonal unit cell (a=2.9 Å;c=14.2 Å) and a largest d-spacing of ˜4.7 Å. The voltage associated withthe lithium intercalation events in LiNiO₂ is above 3V vs. Li/Li+.

Even though all of the octahedral sites in LiNiO₂ are occupied,additional lithium can be inserted into the material, formingLi_(1+x)NiO₂. The additional lithium necessarily occupies sites in closeproximity to other cations with less shielding from the anion array.Thus, the insertion of this additional lithium occurs at lower voltages,<2V vs. Li/Li+ for bulk phase materials.

Other phases that are possible from metal occupation of sites withinclose-packed oxygen arrays include the orthorhombic phasesLi_(1/2)Ni_(1/3)Ta_(1/6)O and Li_(1/2)Ni_(1/3)Nb_(1/6)O in which the Nbor Ta segregate to one set of octahedral sites and the Ni and Li aremixed on the remaining sites. Further examples are the spinel phasesincluding Li_(1/4)Mn_(3/8)Ni_(1/8)O in which Mn and Ni occupy theoctahedral sites and Li occupies ¼ of the tetrahedral sites.

A collective signature of all of the phases described above are theclose packed layers. In the rock salt structure, these give rise to asingle diffraction reflection at ˜2.4 Å, labeled as the (111)reflection. This is the largest symmetry allowed d-spacing in the rocksalt structure. The second largest d-spacing allowed in the rock saltstructure is the (200) peak whose d-spacing is ˜2.1 Å. In lower symmetrystructures such as Li_(1/2)Ni_(1/2)O and Li_(1/2)Ni_(1/3)Ta_(1/6)O,reflections equivalent to the rock salt (111) and (200) reflections areobserved at approximately the same d-spacing but are labeled differentlyand may be split into multiple peaks. For example, in the hexagonal,layered material the rock salt (111) reflection splits into tworeflections, the (006) and the (102) peak, both of which occur at ˜2.4 Åand the rock salt (200) peak becomes the (104) peak, whose d-spacing isalso 2.1 Å. A clear signature that an ordered metal sub-lattice existswithin a material giving rise to structures such as Li_(1/2)Ni_(1/2)O,Li_(1/2)Ni_(1/3)Nb_(1/6)O, and Li_(1/4)Mn_(3/8)Ni_(1/8)O is the presenceof reflections with d-spacings greater than 2.4 Å (Table 1).

TABLE 1 Largest d-spacing (Å) and associated hkl of example materialsderived from metals within octahedral and/or tetrahedral sites createdby close packed oxygen arrays Largest Composition Structure Noted-spacing (Å) hkl NiO rock salt 2.4 (111) Li_(0.1)Ni_(0.9)O rock salt,Li and Ni 2.4 (111) randomly arranged Li_(1/2)Ni_(1/2)O Hexagonal, Liand Ni 4.7 (003) ordered into layers Li_(1/2)Ni_(1/3)Ta_(1/6)OOrthorhombic, Ta and 4.7 (111) Li/Ni ordered Li_(1/4)Mn_(3/8)Ni_(1/8)OCubic, Ni/Mn in octahedral 4.7 (111) sites; Li in tetrahedral sites

Although a range of electrochromic anodic materials have been proposeddate, there is a need for anode films that can be prepared by simplesingle-step deposition processes to produce EC anodes with improvedthermal stability, high optical clarity in their as-deposited states,and that can be tuned via composition and film thickness to adopt a widevariety of area charge capacities and optical switching properties.

Among the various aspects of the present disclosure is the provision ofa process for the preparation of liquid mixtures adapted for thin filmdeposition onto a substrate. The liquid mixture contains a liquid phase(also known as a continuous phase) and a dispersed phase that mayinclude anything from discrete particles to a semi-continuous polymernetwork. If the dispersed phase is a dissolved phase where the dissolvedspecies (e.g. molecules or molecular complexes) are commonly sized onthe order of 1 nm, the liquid mixture may be considered to be asolution. If the dispersed phase is sized between 1 nm and 1 micrometer,the dispersed phase may be considered to be a colloidal dispersionaccording to commonly accepted definitions. If the dispersed phase issized greater than 1 micrometer, the dispersed phase may be consideredto be a coarse dispersion. Sometimes a coarse dispersion may be called asuspension. According to commonly accepted definitions, a suspension maybe further defined as containing particles that are sufficiently largefor sedimentation and will settle over time if undisturbed. According tothe provisions of the present disclosure, when preparing liquid mixturesadapted for thin film deposition onto a substrate, there is benefit ifthe liquid mixture is comprised of a dispersed phase that does notrapidly precipitate. For example, in some embodiments, the liquidmixture is a colloidal dispersion of discrete particles in a continuous,liquid phase. In other embodiments, the liquid mixture comprises anintegrated network (or gel) of either discrete particles or oligomers.In yet other embodiments, the volume fraction of particles (or particledensity) in the liquid mixture may be so low that a significant amountof fluid from the liquid mixture may need to be removed for gel-likeproperties to be recognized. In yet another embodiment, the liquidmixture comprises discrete pre-formed particles that have been dispersedin a liquid phase.

One aspect of the present disclosure is a process for forming amulti-layer electrochromic structure. The process comprises forming aliquid mixture comprising a liquid phase and a dispersed phase,depositing a film of a liquid mixture comprising lithium, nickel, and atleast one bleached state stabilizing element onto a surface of asubstrate, and treating the deposited material to form an anodicelectrochromic layer. The bleached state stabilizing element(s) is/areselected from the group consisting of Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W,B, Al, Ga, In, Si, Ge, Sn, P, Sb and combinations thereof.

A further aspect of the present disclosure is a process for thepreparation of a multi-layer electrochromic structure comprising ananodic electrochromic layer on a first substrate. The process comprisesforming a liquid mixture comprising a liquid phase and a dispersedphase, depositing a film of a liquid mixture comprising lithium, nickel,and at least one bleached state stabilizing element selected from thegroup consisting of Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si,Ge, Sn, P, Sb and combinations thereof, and treating the depositedmaterial to form an anodic electrochromic layer characterized by alargest d-spacing of at least 2.5 Å.

A further aspect of the present disclosure is a process for thepreparation of a multi-layer electrochromic structure comprising ananodic electrochromic layer on a first substrate wherein the anodicelectrochromic layer comprises lithium, nickel, and at least onebleached state stabilizing element selected from the group consisting ofY, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, Sb andcombinations thereof, and the atomic ratio of the amount of lithium tothe combined amount of nickel and the bleached state stabilizingelement(s) is less than 1.75:1, respectively, when the anodicelectrochromic layer is in its fully bleached state. The processcomprises forming a liquid mixture comprising a liquid phase and adispersed phase, depositing a film of a liquid mixture comprisinglithium, nickel, and the bleached state stabilizing element(s), andtreating the deposited material to form the anodic electrochromic layer.

A further aspect of the present disclosure is a multi-layerelectrochromic structure comprising a first substrate and a secondsubstrate, a first and a second electrically conductive layer, a cathodelayer, an anodic electrochromic layer, and an ion conductor layer,wherein the first electrically conductive layer is between the firstsubstrate and the anodic electrochromic layer, the anodic electrochromiclayer is between the first electrically conductive layer and the ionconductor layer, the second electrically conductive layer is between thecathode layer and the second substrate, the cathode layer is between thesecond electrically conductive layer and the ion conductor layer, andthe ion conductor layer is between the cathode layer and anodicelectrochromic layer. The anodic electrochromic layer comprises lithium,nickel, and at least one bleached state stabilizing element selectedfrom the group consisting of Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga,In, Si, Ge, Sn, P, Sb and combinations thereof, wherein the atomic ratioof the amount of lithium to the combined amount of nickel, and thebleached state stabilizing element(s) in the anodic electrochromic layeris less than 1.75:1, respectively, when the anodic electrochromic layeris in its fully bleached state. The process comprises forming a liquidmixture comprising a liquid phase and a dispersed phase, depositing afilm of a liquid mixture comprising lithium, nickel, and the bleachedstate stabilizing element(s), and treating the deposited material toform the anodic electrochromic layer.

A further aspect of the present disclosure is a multi-layerelectrochromic structure comprising a first substrate and a secondsubstrate, a first and a second electrically conductive layer, a cathodelayer, an anodic electrochromic layer, and an ion conductor layer,wherein the first electrically conductive layer is between the firstsubstrate and the anodic electrochromic layer, the anodic electrochromiclayer is between the first electrically conductive layer and the ionconductor layer, the second electrically conductive layer is between thecathode layer and the second substrate, the cathode layer is between thesecond electrically conductive layer and the ion conductor layer, andthe ion conductor layer is between the cathode layer and the anodicelectrochromic layer. The anodic electrochromic layer comprises lithium,nickel, and at least one bleached state stabilizing element selectedfrom the group consisting of Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga,In, Si, Ge, Sn, P, Sb and combinations thereof, wherein the anodicelectrochromic layer is characterized by a largest d-spacing of at least2.5 Å. The process comprises forming a liquid mixture comprising aliquid phase and a dispersed phase, depositing a film of a liquidmixture comprising lithium, nickel, and the bleached state stabilizingelement(s), and treating the deposited material to form the anodicelectrochromic layer.

A further aspect of the present disclosure is a process for thepreparation of a multi-layer structure comprising a lithium nickel oxidefilm prepared in accordance with the present disclosure.

A further aspect of the present disclosure is a process for thepreparation of a multi-layer electrochromic structure comprising ananodic electrochromic film prepared in accordance with the presentdisclosure.

A further aspect of the present disclosure is a process for forming amulti-layer structure. The process comprises depositing a film of aliquid mixture onto a surface of a substrate and treating the depositedfilm to form an anodic electrochromic layer on the surface of thesubstrate wherein the liquid mixture comprises a hydrolysable nickel, ahydrolysable bleached state stabilizing element composition and/or ahydrolysable lithium composition.

A further aspect of the present disclosure is a multi-layerelectrochromic structure comprising an electrochromic lithium nickeloxide film prepared in accordance with the present disclosure.

A further aspect of the present disclosure is a process for forming amulti-layer electrochromic structure. The process comprises depositing afilm of a liquid mixture onto a surface of a substrate, and treating thedeposited film to form an anodic electrochromic layer, the liquidmixture comprising a continuous phase and a dispersed phase, thedispersed phase comprising metal oxide particles, metal hydroxideparticles, metal alkoxide particles, metal alkoxide oligomers, gels orparticles, or a combination thereof having a number average size of atleast 5 nm.

Other objects and features will be in part apparent and in part pointedout hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-section of a multi-layer electrochromicstructure comprising an anodic electrochromic layer of the presentdisclosure.

FIG. 2 is a schematic cross-section of an alternative embodiment of amulti-layer electrochromic structure comprising an anodic electrochromiclayer of the present disclosure.

Corresponding reference characters indicate corresponding partsthroughout the drawings. Additionally, relative thicknesses of thelayers in the different figures do not represent the true relationshipin dimensions. For example, the substrates are typically much thickerthan the other layers. The figures are drawn only for the purpose toillustrate connection principles, not to give any dimensionalinformation.

Abbreviations and Definitions

The following definitions and methods are provided to better define thepresent disclosure and to guide those of ordinary skill in the art inthe practice of the present disclosure. Unless otherwise noted, termsare to be understood according to conventional usage by those ofordinary skill in the relevant art.

Unless otherwise indicated, the alkyl groups described herein arepreferably lower alkyls containing from one to eight carbon atoms in theprincipal chain and up to 20 carbon atoms. They may be linear orbranched, chain or cyclic and include methyl, ethyl, propyl, isopropyl,butyl, hexyl, cyclohexyl and the like.

The terms “amine” or “amino,” as used herein alone or as part of anothergroup, represents a group of formula —N(R⁸)(R⁹), wherein R⁸ and R⁹ areindependently hydrogen, hydrocarbyl, substituted hydrocarbyl, silyl, orR⁸ and R⁹ taken together form a substituted or unsubstituted cyclic orpolycyclic moiety, each as defined in connection with such terms,typically having from 3 to 8 atoms in the ring. “Substituted amine,” forexample, refers to a group of formula —N(R⁸)(R⁹), wherein at least oneof R⁸ and R⁹ are other than hydrogen. “Unsubstituted amine,” forexample, refers to a group of formula —N(R⁸)(R⁹), wherein R⁸ and R⁹ areboth hydrogen.

The term “alkoxide” as used herein refers to a deprotonated alcohol andis typically used to describe a metal complex of the form M¹—OR where M¹is a metal.

The term “amide” as used herein in connection with a metal complexrefers to a metal complex of the form M¹—N(R⁸)(R⁹) where M¹ is a metal.

The term “aryl” as used herein alone or as part of another group denotesoptionally substituted homocyclic aromatic groups, preferably monocyclicor bicyclic groups containing from 6 to 12 carbons in the ring portion,such as phenyl, biphenyl, naphthyl, substituted phenyl, substitutedbiphenyl or substituted naphthyl. Phenyl and substituted phenyl are themore preferred aryl.

The terms “anodic electrochromic layer” and “anodic electrochromicmaterial” refer to an electrode layer or electrode material,respectively, that upon the removal of ions and electrons becomes lesstransmissive to electromagnetic radiation.

The term “bleach” refers to the transition of an electrochromic materialfrom a first optical state to a second optical state wherein the firstoptical state is less transmissive than the second optical state.

The term “bleached state stabilizing element” as used herein means anelement that acts to increase the bleached state voltage of lithiumnickel oxide without adversely affecting the transmissivity of its fullybleached state, such as by decreasing the transmissivity of the fullybleached state or by resulting in a shift in the color coordinates ofthe fully bleached state, such as the creation of a yellow or brown hueto said fully bleached state. In general, bleached state stabilizingelements are those elements that readily form as colorless or lightlycolored oxides solids in their highest oxidation state (i.e., formallyd0), and where the highest oxidation state is 3+ or greater.

The term “bleached state voltage” refers to the open circuit voltage(V^(oc)) of the anodic electrochromic layer versus Li/Li+ in anelectrochemical cell in a propylene carbonate solution containing 1Mlithium perchlorate when the transmissivity of said layer is at 95% ofits “fully bleached state” transmissivity.

The terms “cathodic electrochromic layer” and “cathodic electrochromicmaterial” refer to an electrode layer or electrode material,respectively, that upon the insertion of ions and electrons becomes lesstransmissive to electromagnetic radiation.

The term “coloration efficiency” or “CE” refers to a property of anelectrochromic layer that quantifies how a layer's optical densitychanges as a function of its state of charge. CE can vary significantlydepending on layer preparation due to differences in structure, materialphases, and/or composition. These differences affect the probability ofelectronic transitions that are manifest as color. As such, CE is asensitive and quantitative descriptor of an electrochromic layerencompassing the ensemble of the identity of the redox centers, theirlocal environments, and their relative ratios. CE is calculated from theratio of the change in optical absorbance to the amount of chargedensity passed. In the absence of significant changes in reflectivity,this wavelength dependent property can be measured over a transition ofinterest using the following equation:

${CE}_{\lambda} = \frac{\left( \frac{T_{ini}}{T_{final}} \right)}{Q_{A}}$where Q_(A) is the charge per area passed, T_(ini) is the initialtransmission, and T_(final) is the final transmission. For anodicallycoloring layers this value is negative, and may also be stated inabsolute (non-negative) values. A simple electro-optical setup thatsimultaneously measures transmission and charge can be used to calculateCE. Alternatively, the end transmission states can be measured ex situbefore and after electrical switching. CE is sometimes alternativelyreported on a natural log basis, in which case the reported values areapproximately 2.3 times larger.

The term “darken” refers to the transition of an electrochromic materialfrom a first optical state to a second optical state wherein the firstoptical state is more transmissive than the second optical state.

The term “electrochromic material” refers to materials that change intransmissivity to electromagnetic radiation, reversibly, as a result ofthe insertion or extraction of ions and electrons. For example, anelectrochromic material may change between a colored, translucent stateand a transparent state.

The term “electrochromic layer” refers to a layer comprising anelectrochromic material.

The term “electrode layer” refers to a layer capable of conducting ionsas well as electrons. The electrode layer contains a species that can bereduced when ions are inserted into the material and contains a speciesthat can be oxidized when ions are extracted from the layer. This changein oxidation state of a species in the electrode layer is responsiblefor the change in optical properties in the device.

The term “electrical potential,” or simply “potential,” refers to thevoltage occurring across a device comprising an electrode/ionconductor/electrode assembly.

The term “electrochemically and optically matched” (EOM) refers to a setof cathode and anode electrochromic films with similar chargecapacities, that are in their complementary optical states (e.g., bothin their bleached state, or both in their darkened state or both in anintermediate state of coloration) such that when joined together by asuitable ion-conducting and electrically insulating layer, a functionalelectrochromic device is formed that shows reversible switchingbehavior.

The term “fully bleached state” as used in connection with an anodicelectrochromic material refers to the state of maximum transmissivity ofan anodic electrochromic layer in an electrochemical cell at or above1.5V versus Li/Li+ in a propylene carbonate solution containing 1 Mlithium perchlorate at 25° C. (under anhydrous conditions and in an Aratmosphere).

The terms “halide,” “halogen” or “halo” as used herein alone or as partof another group refer to chlorine, bromine, fluorine, and iodine.

The term “heteroatom” shall mean atoms other than carbon and hydrogen.

The terms “hydrocarbon” and “hydrocarbyl” as used herein describeorganic compounds or radicals consisting exclusively of the elementscarbon and hydrogen. These moieties include alkyl, alkenyl, alkynyl, andaryl moieties. These moieties also include alkyl, alkenyl, alkynyl, andaryl moieties substituted with other aliphatic or cyclic hydrocarbongroups, such as alkaryl, alkenaryl and alkynaryl. Unless otherwiseindicated, these moieties preferably comprise 1 to 20 carbon atoms.

The term “rock salt” as used herein describes a cubic structure in whichmetal cations (“M”) occupy all of the octahedral sites of a close packedoxygen array, resulting in the stoichiometry MO. Furthermore, the metalsare indistinguishable from one another regardless of whether the metalsare the same element or a random distribution of different elements.

The term “silyl” as used herein describes substituents of the generalformula —Si(X⁸)(X⁹)(X¹⁰) where X⁸, X⁹, and X¹⁰ are independentlyhydrocarbyl or substituted hydrocarbyl.

The “substituted hydrocarbyl” moieties described herein are hydrocarbylmoieties which are substituted with at least one atom other than carbon,including moieties in which a carbon chain atom is substituted with ahetero atom such as nitrogen, oxygen, silicon, phosphorous, boron,sulfur, or a halogen atom. These substituents include halogen,heterocyclo, alkoxy, alkenoxy, alkynoxy, aryloxy, hydroxy, protectedhydroxy, keto, acyl, acyloxy, nitro, amino, amido, nitro, cyano, thiol,ketals, acetals, esters, ethers, and thioethers.

The term “transmissivity” refers to the fraction of light transmittedthrough an electrochromic film. Unless otherwise stated, thetransmissivity of an electrochromic film is represented by the numberT_(vis). T_(vis) is calculated/obtained by integrating the transmissionspectrum in the wavelength range of 400-730 nm using the spectralphotopic efficiency I_p(lambda) (CIE, 1924) as a weighting factor. (Ref:ASTM E1423).

The term “transparent” is used to denote substantial transmission ofelectromagnetic radiation through a material such that, for example,bodies situated beyond or behind the material can be distinctly seen orimaged using appropriate image sensing technology.

Embodiments

In accordance with one aspect of the present disclosure, anodicelectrochromic materials comprising lithium, nickel, and at least onebleached state stabilizing element are prepared from a liquid mixturecomprising lithium, nickel, and the bleached state stabilizingelement(s). The resulting anodic electrochromic films have a range ofdesirable properties and characteristics. For example, in one embodimentthe anodic electrochromic material may have a bleached state voltagevalue significantly greater than 2.0V. In another embodiment, the anodicelectrochromic material is provided in an electrochemically andoptically matched (EOM) state relative to a cathodic electrochromicmaterial in its fully bleached state for use in an electrochromicdevice. In another embodiment, the anodic electrochromic material isrelatively stable; for example, the lithium nickel oxide material doesnot darken from its fully bleached state or deactivate (e.g., remaintransparent but no longer function as an electrochromic anode materialor film) at elevated temperatures in the presence of ambient air.

Advantageously, bleached state stabilizing element(s) promote theformation of electrochromic lithium nickel oxide materials havingfavorable bleached state characteristics. In one embodiment, theelectrochromic nickel oxide material comprises a bleached statestabilizing element selected from the group consisting of Group 3, Group4, Group 5, Group 6, Group 13, Group 14 and Group 15 elements (IUPACclassification) and combinations thereof. For example, in oneembodiment, the electrochromic nickel oxide material comprises yttrium.By way of further example, in one embodiment, the electrochromic nickeloxide material comprises a naturally occurring Group 4 metal, i.e.,titanium, zirconium, hafnium or a combination thereof. By way of furtherexample, in one embodiment, the electrochromic nickel oxide materialcomprises a naturally occurring Group 5 metal, i.e., vanadium, niobium,tantalum or a combination thereof. By way of further example, in oneembodiment, the electrochromic nickel oxide material comprises a Group 6metal, e.g., molybdenum, tungsten or a combination thereof. By way offurther example, in one embodiment, the electrochromic nickel oxidematerial comprises a Group 13 element, e.g., boron, aluminum, gallium,indium or a combination thereof. By way of further example, in oneembodiment, the electrochromic nickel oxide material comprises a Group14 element selected from silicon, germanium, tin and combinationsthereof. By way of further example, in one embodiment, theelectrochromic nickel oxide material comprises a Group 15 elementselected from phosphorous, antimony, or a combination thereof. By way offurther example, in one embodiment, the electrochromic nickel oxidematerial comprises a bleached state stabilizing element selected fromthe group consisting of Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In,Si, Ge, Sn, P, Sb and combinations thereof. In certain exemplaryembodiments, the electrochromic nickel oxide material comprises ableached state stabilizing element selected from the group consisting ofY, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, andcombinations thereof. In certain exemplary embodiments, theelectrochromic nickel oxide material comprises a bleached statestabilizing element selected from the group consisting of Y, Ti, Zr, Hf,V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn and combinations thereof. Incertain exemplary embodiments, the electrochromic nickel oxide materialcomprises a bleached state stabilizing element selected from the groupconsisting of Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, andcombinations thereof. In certain exemplary embodiments, theelectrochromic nickel oxide material comprises a bleached statestabilizing element selected from the group consisting of Y, Ti, Zr, Hf,V, Nb, Ta, Mo, W, and combinations thereof. In certain exemplaryembodiments, the electrochromic nickel oxide material comprises ableached state stabilizing element selected from the group consisting ofTi, Zr, Hf, V, Nb, Ta, Mo, W, and combinations thereof. In certainexemplary embodiments, the electrochromic nickel oxide materialcomprises a bleached state stabilizing element selected from the groupconsisting of Ti, Zr, Hf, Ta, V, Nb, W and combinations thereof. Incertain exemplary embodiments, the electrochromic nickel oxide materialcomprises a bleached state stabilizing element selected from the groupconsisting of Ti, Zr, Hf and combinations thereof. In certain exemplaryembodiments, the electrochromic nickel oxide material comprises ableached state stabilizing element selected from the group consisting ofZr, Hf, and a combination thereof. In certain exemplary embodiments, theelectrochromic nickel oxide material comprises a bleached statestabilizing element selected from the group consisting of V, Nb, Ta, anda combination thereof. In certain exemplary embodiments, theelectrochromic nickel oxide material comprises a bleached statestabilizing element selected from the group consisting of Nb, Ta, and acombination thereof. In certain exemplary embodiments, theelectrochromic nickel oxide material comprises a bleached statestabilizing element selected from the group consisting of Mo and W and acombination thereof. By way of further example, in certain exemplaryembodiments, the electrochromic nickel oxide material comprises Ti. Byway of further example, in certain exemplary embodiments, theelectrochromic nickel oxide material comprises Zr. By way of furtherexample, in certain exemplary embodiments, the electrochromic nickeloxide material comprises Hf. By way of further example, in certainexemplary embodiments, the electrochromic nickel oxide materialcomprises V. By way of further example, in certain exemplaryembodiments, the electrochromic nickel oxide material comprises Nb. Byway of further example, in certain exemplary embodiments, theelectrochromic nickel oxide material comprises Ta. By way of furtherexample, in certain exemplary embodiments, the electrochromic nickeloxide material comprises Mo. By way of further example, in certainexemplary embodiments, the electrochromic nickel oxide materialcomprises W. By way of further example, in certain exemplaryembodiments, the electrochromic nickel oxide material comprises B. Byway of further example, in certain exemplary embodiments, theelectrochromic nickel oxide material comprises Al. By way of furtherexample, in certain exemplary embodiments, the electrochromic nickeloxide material comprises Ga. By way of further example, in certainexemplary embodiments, the electrochromic nickel oxide materialcomprises In. By way of further example, in certain exemplaryembodiments, the electrochromic nickel oxide material comprises Si. Byway of further example, in certain exemplary embodiments, theelectrochromic nickel oxide material comprises Ge. By way of furtherexample, in certain exemplary embodiments, the electrochromic nickeloxide material comprises Sn. By way of further example, in certainexemplary embodiments, the electrochromic nickel oxide materialcomprises P. By way of further example, in certain exemplaryembodiments, the electrochromic nickel oxide material comprises Sb.

In one embodiment, the anodic electrochromic film comprising a lithiumnickel oxide material prepared by the process of the present disclosureis characterized by a largest d-spacing of at least 2.5 Å by diffractiontechniques such as electron diffraction (“ED”) and X-ray diffraction(“XRD”) analysis. For example, in one embodiment the lithium nickeloxide material is characterized by a largest d-spacing of at least 2.75Å. By way of further example, in one embodiment the anodicelectrochromic material is characterized by a largest d-spacing of atleast 3 Å. By way of further example, in one embodiment the anodicelectrochromic material is characterized by a largest d-spacing of atleast 3.25 Å. By way of further example, in one embodiment the anodicelectrochromic material is characterized by a largest d-spacing of atleast 3.5 Å. By way of further example, in one embodiment the anodicelectrochromic material is characterized by a largest d-spacing of atleast 4 Å. By way of further example, in one embodiment the anodicelectrochromic material is characterized by a largest d-spacing of atleast 4.5 Å.

In accordance with one aspect of the present disclosure, the relativeamounts of lithium, nickel and bleached state stabilizing element(s) inthe electrochromic lithium nickel oxide material are controlled suchthat an atomic ratio of the amount of lithium to the combined amount ofnickel and all bleached state stabilizing element(s) in theelectrochromic lithium nickel oxide material is generally at least about0.4:1, respectively, wherein the bleached state stabilizing element(s)is/are selected from the group consisting of Group 3, Group 4, Group 5,Group 6, Group 13, Group 14 and Group 15 elements, and combinationsthereof. For example, in one embodiment, the atomic ratio of lithium tothe combined amount of nickel and all bleached state stabilizingelements, i.e., Li:[Ni+M], in the electrochromic lithium nickel oxidematerial is at least about 0.4:1, respectively, wherein M is a bleachedstate stabilizing element selected from the group consisting of Y, Ti,Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, Sb, andcombinations thereof; stated differently, the ratio of the amount oflithium to the combined amount of Ni, Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W,B, Al, Ga, In, Si, Ge, Sn, P, and Sb, in the electrochromic lithiumnickel oxide material is at least 0.4:1 (atomic ratio). By way offurther example, in one such embodiment the atomic ratio of lithium tothe combined amount of nickel and all bleached state stabilizingelement(s) M in the electrochromic lithium nickel oxide material (e.g.,wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn,P, Sb or a combination thereof) is at least about 0.75:1, respectively.By way of further example, in one such embodiment the atomic ratio oflithium to the combined amount of nickel and all bleached statestabilizing element(s) M in the electrochromic lithium nickel oxidematerial (e.g., wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga,In, Si, Ge, Sn, P, Sb or a combination thereof) is at least about 0.9:1,respectively. By way of further example, in one such embodiment theatomic ratio of lithium to the combined amount of nickel and allbleached state stabilizing element(s) M in the electrochromic lithiumnickel oxide material (e.g., wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo,W, B, Al, Ga, In, Si, Ge, Sn, P, Sb or a combination thereof) is atleast about 1:1, respectively. By way of further example, in one suchembodiment the atomic ratio of lithium to the combined amount of nickeland all bleached state stabilizing element(s) M in the electrochromiclithium nickel oxide material (e.g., wherein M is Y, Ti, Zr, Hf, V, Nb,Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, Sb or a combination thereof) isat least about 1.25:1, respectively. By way of further example, in onesuch embodiment the atomic ratio of lithium to the combined amount ofnickel and all bleached state stabilizing element(s) M in theelectrochromic lithium nickel oxide material (e.g., wherein M is Y, Ti,Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, Sb or acombination thereof) is at least about 1.5:1, respectively. By way offurther example, in one such embodiment the atomic ratio of lithium tothe combined amount of nickel and all bleached state stabilizingelement(s) M in the electrochromic lithium nickel oxide material (e.g.,wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn,P, Sb or a combination thereof) is at least about 2:1, respectively. Byway of further example, in one such embodiment the atomic ratio oflithium to the combined amount of nickel and all bleached statestabilizing element(s) M in the electrochromic lithium nickel oxidematerial (e.g., wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga,In, Si, Ge, Sn, P, Sb or a combination thereof) is at least about 2.5:1,respectively. In certain embodiments, the atomic ratio of lithium to thecombined amount of nickel and all bleached state stabilizing element(s)M in the electrochromic lithium nickel oxide material (e.g., wherein Mis Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, Sb ora combination thereof) will not exceed about 4:1, respectively. In someembodiments, therefore, the atomic ratio of lithium to the combinedamount of nickel and all bleached state stabilizing element(s) M in theelectrochromic lithium nickel oxide material (e.g., wherein M is Y, Ti,Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, Sb or acombination thereof) will be in the range about 0.75:1 to about 3:1,respectively. In some embodiments, therefore, the atomic ratio oflithium to the combined amount of nickel and all bleached statestabilizing element(s) M in the electrochromic lithium nickel oxidematerial (e.g., wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga,In, Si, Ge, Sn, P, Sb or a combination thereof) will be in the rangeabout 0.9:1 to about 2.5:1, respectively. In some embodiments,therefore, the atomic ratio of lithium to the combined amount of nickeland all bleached state stabilizing element(s) M in the electrochromiclithium nickel oxide material (e.g., wherein M is Y, Ti, Zr, Hf, V, Nb,Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, Sb or a combination thereof)will be in the range about 1:1 to about 2.5:1, respectively. In someembodiments, therefore, the atomic ratio of lithium to the combinedamount of nickel and all bleached state stabilizing element(s) M in theelectrochromic lithium nickel oxide material (e.g., wherein M is Y, Ti,Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, Sb or acombination thereof) will be in the range about 1.1:1 to about 1.5:1,respectively. In some embodiments, therefore, the atomic ratio oflithium to the combined amount of nickel and all bleached statestabilizing element(s) M in the electrochromic lithium nickel oxidematerial (e.g., wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga,In, Si, Ge, Sn, P, Sb or a combination thereof) will be in the rangeabout 1.5:1 to about 2:1, respectively. In some embodiments, therefore,the atomic ratio of lithium to the combined amount of nickel and allbleached state stabilizing element(s) M in the electrochromic lithiumnickel oxide material (e.g., wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo,W, B, Al, Ga, In, Si, Ge, Sn, P, Sb or a combination thereof) will be inthe range about 2:1 to about 2.5:1, respectively.

In one embodiment, the electrochromic nickel oxide material comprisesone or more bleached state stabilizing elements selected from the groupconsisting of Group 3, Group 4, Group 5, Group 6, Group 13, Group 14 andGroup 15 elements (IUPAC classification), and combinations thereof inaddition to nickel. In such embodiments, the relative amounts oflithium, nickel, and the bleached state stabilizing element(s) in theelectrochromic lithium nickel oxide material are controlled such that anatomic ratio of the amount of lithium to the combined amount of nickel,and bleached state stabilizing element(s) in the electrochromic lithiumnickel oxide material is generally less than about 1.75:1, respectively,wherein the bleached state stabilizing element(s) is/are selected fromthe group consisting of Group 3, Group 4, Group 5, Group 6, Group 13,Group 14 and Group 15 elements, and combinations thereof, and theelectrochromic nickel oxide material is in its fully bleached state. Forexample, in one embodiment, the atomic ratio of lithium to the combinedamount of nickel and all bleached state stabilizing elements, i.e.,Li:[Ni+M], in the electrochromic lithium nickel oxide material is lessthan about 1.75:1, respectively, wherein M is a bleached statestabilizing element selected from the group consisting of Y, V, Nb, Ta,Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, Sb, and combinations thereof andthe electrochromic nickel oxide material is in its fully bleached state;stated differently, the ratio of the amount of lithium to the combinedamount of Ni, Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge,Sn, P, and Sb, in the electrochromic lithium nickel oxide material isless than 1.75:1 (atomic ratio), respectively, when the electrochromiclithium nickel oxide material is in its fully bleached state. Forexample, in one such embodiment the atomic ratio of lithium to thecombined amount of Ni, Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In,Si, Ge, Sn, P, and Sb, in the electrochromic lithium nickel oxidematerial is less than 1.5:1, respectively, when the electrochromiclithium nickel oxide material is in its fully bleached state. By way offurther example, in one such embodiment the atomic ratio of lithium tothe combined amount of Ni, Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga,In, Si, Ge, Sn, P, and Sb, in the electrochromic lithium nickel oxidematerial is less than 1.45:1, respectively, when the electrochromiclithium nickel oxide material is in its fully bleached state. By way offurther example, in one such embodiment the atomic ratio of lithium tothe combined amount of Ni, Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga,In, Si, Ge, Sn, P, and Sb, in the electrochromic lithium nickel oxidematerial is less than 1.4:1, respectively, when the electrochromiclithium nickel oxide material is in its fully bleached state. By way offurther example, in one such embodiment the atomic ratio of lithium tothe combined amount of Ni, Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga,In, Si, Ge, Sn, P, and Sb, in the electrochromic lithium nickel oxidematerial is less than 1.35:1, respectively, when the electrochromiclithium nickel oxide material is in its fully bleached state. By way offurther example, in one such embodiment the atomic ratio of lithium tothe combined amount of Ni, Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga,In, Si, Ge, Sn, P, and Sb, in the electrochromic lithium nickel oxidematerial is less than 1.3:1, respectively, when the electrochromiclithium nickel oxide material is in its fully bleached state. By way offurther example, in one such embodiment the atomic ratio of lithium tothe combined amount of Ni, Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga,In, Si, Ge, Sn, P, and Sb, in the electrochromic lithium nickel oxidematerial is less than 1.25:1, respectively, when the electrochromiclithium nickel oxide material is in its fully bleached state. By way offurther example, in one such embodiment the atomic ratio of lithium tothe combined amount of Ni, Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga,In, Si, Ge, Sn, P, and Sb, in the electrochromic lithium nickel oxidematerial is less than 1.2:1, respectively, when the electrochromiclithium nickel oxide material is in its fully bleached state. By way offurther example, in one such embodiment the atomic ratio of lithium tothe combined amount of Ni, Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga,In, Si, Ge, Sn, P, and Sb, in the electrochromic lithium nickel oxidematerial is less than 1.15:1, respectively, when the electrochromiclithium nickel oxide material is in its fully bleached state. By way offurther example, in one such embodiment the atomic ratio of lithium tothe combined amount of Ni, Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga,In, Si, Ge, Sn, P, and Sb, in the electrochromic lithium nickel oxidematerial is less than 1.1:1, respectively, when the electrochromiclithium nickel oxide material is in its fully bleached state. By way offurther example, in one such embodiment the atomic ratio of lithium tothe combined amount of Ni, Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga,In, Si, Ge, Sn, P, and Sb, in the electrochromic lithium nickel oxidematerial is less than 1.05:1, respectively, when the electrochromiclithium nickel oxide material is in its fully bleached state. By way offurther example, in one such embodiment the atomic ratio of lithium tothe combined amount of Ni, Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga,In, Si, Ge, Sn, P, and Sb, in the electrochromic lithium nickel oxidematerial is less than 1:1, respectively, when the electrochromic lithiumnickel oxide material is in its fully bleached state. By way of furtherexample, in one such embodiment the atomic ratio of lithium to thecombined amount of Ni, Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In,Si, Ge, Sn, P, and Sb, in the electrochromic lithium nickel oxidematerial is in the range of about 0.4:1 to 1.5:1, respectively, when theelectrochromic lithium nickel oxide material is in its fully bleachedstate. By way of further example, in one such embodiment the atomicratio of lithium to the combined amount of Ni, Y, Ti, Zr, Hf, V, Nb, Ta,Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, and Sb, in the electrochromiclithium nickel oxide material is in the range of about 0.5:1 to 1.4:1,respectively, when the electrochromic lithium nickel oxide material isin its fully bleached state. In certain embodiments, the atomic ratio oflithium to the combined amount of Ni, Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W,B, Al, Ga, In, Si, Ge, Sn, P, and Sb, in the electrochromic lithiumnickel oxide material is in the range of about 0.6:1 to 1.35:1,respectively, when the electrochromic lithium nickel oxide material isin its fully bleached state. In certain embodiments, the atomic ratio oflithium to the combined amount of Ni, Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W,B, Al, Ga, In, Si, Ge, Sn, P, and Sb, in the electrochromic lithiumnickel oxide material is in the range of about 0.7:1 to 1.35:1,respectively, when the electrochromic lithium nickel oxide material isin its fully bleached state. In certain embodiments, the atomic ratio oflithium to the combined amount of Ni, Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W,B, Al, Ga, In, Si, Ge, Sn, P, and Sb, in the electrochromic lithiumnickel oxide material is in the range of about 0.8:1 to 1.35:1,respectively, when the electrochromic lithium nickel oxide material isin its fully bleached state. In certain embodiments, the atomic ratio oflithium to the combined amount of Ni, Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W,B, Al, Ga, In, Si, Ge, Sn, P, and Sb, in the electrochromic lithiumnickel oxide material is in the range of about 0.9:1 to 1.35:1,respectively, when the electrochromic lithium nickel oxide material isin its fully bleached state.

In general, increasing the total amount of the bleached statestabilizing element(s) relative to the amount of nickel in theelectrochromic lithium nickel oxide material increases the stability ofthe bleached state and the bleached state voltage of the material but italso tends to decrease its volumetric charge capacity. Anodicelectrochromic lithium nickel oxide material having large amounts ofbleached state stabilizing element(s) relative to nickel, such as thosein which the atomic ratio of the combined amount of all such bleachedstate stabilizing elements M to the combined amount of nickel and allsuch bleached state stabilizing elements M (i.e., M:[Ni+M]) is greaterthan about 0.8:1, respectively, tend to have stable fully bleachedstates, but sub-optimal charge capacities and darkened statetransmissivities. Thus, in certain embodiments it is preferred that theatomic ratio of the combined amount of all such bleached statestabilizing elements M to the combined amount of nickel and all suchbleached state stabilizing elements M in the electrochromic lithiumnickel oxide material be less than about 0.8:1 (i.e., M:[Ni+M]). Forexample, in one such embodiment the atomic ratio of the combined amountof all such bleached state stabilizing elements M (e.g., wherein M is Y,Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, Sb or acombination thereof) to the combined amount of nickel and all suchbleached state stabilizing elements M in the electrochromic lithiumnickel oxide material is less than about 0.7:1 (i.e., M:[Ni+M]). By wayof further example, in one such embodiment the atomic ratio of thecombined amount of all such bleached state stabilizing elements M (e.g.,wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn,P, Sb or a combination thereof) to the combined amount of nickel and allsuch bleached state stabilizing elements M in the electrochromic lithiumnickel oxide material is less than about 0.6:1. By way of furtherexample, in one such embodiment the atomic ratio of the combined amountof all such bleached state stabilizing elements M (e.g., wherein M is Y,Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, Sb or acombination thereof) to the combined amount of nickel and all suchbleached state stabilizing elements M in the electrochromic lithiumnickel oxide material is less than about 0.5:1. By way of furtherexample, in one such embodiment the atomic ratio of the combined amountof all such bleached state stabilizing elements M (e.g., wherein M is Y,Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, Sb or acombination thereof) to the combined amount of nickel and all suchbleached state stabilizing elements M in the electrochromic lithiumnickel oxide material is less than about 0.4:1.

Conversely, anodic electrochromic lithium nickel oxide materials havingsmall amounts of bleached state stabilizing elements (in combination)relative to nickel, such as those in which the atomic ratio of thecombined amount of all such bleached state stabilizing elements to thecombined amount of nickel and all such bleached state stabilizingelements (i.e., M:[Ni+M])) is less than about 0.025:1, respectively,tend to have relatively high charge capacities but less stable fullybleached states. Thus, in certain embodiments it is preferred that theratio (atomic) of the combined amount of all such bleached statestabilizing elements M to the combined amount of nickel and all suchbleached state stabilizing elements M in the electrochromic lithiumnickel oxide material be greater than about 0.03:1 (i.e., M:[Ni+M]). Forexample, in one such embodiment the atomic ratio of the combined amountof all such bleached state stabilizing elements M (e.g., wherein M is Y,Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, Sb or acombination thereof) to the combined amount of nickel and all suchbleached state stabilizing elements M in the electrochromic lithiumnickel oxide material is greater than about 0.04:1 (i.e., M:[Ni+M]). Byway of further example, in one such embodiment the atomic ratio of thecombined amount of all such bleached state stabilizing elements M (e.g.,wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn,P, Sb or a combination thereof) to the combined amount of nickel and allsuch bleached state stabilizing elements M in the electrochromic lithiumnickel oxide material is greater than about 0.05:1. By way of furtherexample, in one such embodiment the atomic ratio of the combined amountof all such bleached state stabilizing elements M (e.g., wherein M is Y,Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, Sb or acombination thereof) to the combined amount of nickel and all suchbleached state stabilizing elements M in the electrochromic lithiumnickel oxide material is greater than about 0.075:1. By way of furtherexample, in one such embodiment the atomic ratio of the combined amountof all such bleached state stabilizing elements M (e.g., wherein M is Y,Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, Sb or acombination thereof) to the combined amount of nickel and all suchbleached state stabilizing elements M in the electrochromic lithiumnickel oxide material is greater than about 0.1:1.

In general, the ratio (atomic) of the combined amount of all suchbleached state stabilizing elements to the combined amount of nickel andall such bleached state stabilizing elements M (e.g., wherein M is Y,Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, Sb or acombination thereof) in the anodic electrochromic lithium nickel oxidematerial will typically be in the range of about 0.025:1 to about 0.8:1(M:[Ni+M]). For example, in one such embodiment the atomic ratio of thecombined amount of all such bleached state stabilizing element(s) M tothe combined amount of nickel and all such bleached state stabilizingelements M in the anodic electrochromic lithium nickel oxide materialwill typically be in the range of about 0.05:1 and about 0.7:1(M:[Ni+M]). By way of further example, in one such embodiment the atomicratio of the combined amount of all such bleached state stabilizingelement(s) M to the combined amount of nickel and all such bleachedstate stabilizing elements M in the anodic electrochromic lithium nickeloxide material will typically be in the range of about 0.075:1 and about0.6:1 (M:[Ni+M]).

In one embodiment, the anodic electrochromic lithium nickel oxidematerial has a bleached state voltage that is at least 2V. For example,in one embodiment the anodic electrochromic lithium nickel oxidematerial has a bleached state voltage of at least 2.5V. By way offurther example, in one embodiment the anodic electrochromic lithiumnickel oxide material has a bleached state voltage of at least 3V. Byway of further example, in one embodiment the anodic electrochromiclithium nickel oxide material has a bleached state voltage of at least3.5V.

Electrochromic Stacks and Devices

FIG. 1 depicts a cross-sectional structural diagram of an electrochromicstructure 1 having an anodic electrochromic layer comprising lithium,nickel, and at least one bleached state stabilizing element inaccordance with one embodiment of the present disclosure. Moving outwardfrom the center, electrochromic structure 1 comprises an ion conductorlayer 10. Anode layer 20 (an anodic electrochromic layer comprisinglithium, nickel, and at least one bleached state stabilizing element asdescribed in greater detail elsewhere herein) is on one side of and incontact with a first surface of ion conductor layer 10. Cathode layer 21is on the other side of and in contact with a second surface of ionconductor layer 10. The central structure, that is, layers 20, 10, 21,is positioned between first and second electrically conductive layers 22and 23 which, in turn, are arranged against outer substrates 24, 25.Elements 22, 20, 10, 21, and 23 are collectively referred to as anelectrochromic stack 28.

Ion conductor layer 10 serves as a medium through which lithium ions aretransported (in the manner of an electrolyte) when the electrochromicdevice transforms between the bleached state and the darkened state. Ionconductor layer 10 comprises an ion conductor material and may betransparent or non-transparent, colored or non-colored, depending on theapplication. Preferably, ion conductor layer 10 is highly conductive tolithium ions and has sufficiently low electron conductivity thatnegligible electron transfer takes place during normal operation.

Some non-exclusive examples of electrolyte types are: solid polymerelectrolytes (SPE), such as poly(ethylene oxide) with a dissolvedlithium salt; gel polymer electrolytes (GPE), such as mixtures ofpoly(methyl methacrylate) and propylene carbonate with a lithium salt;composite gel polymer electrolytes (CGPE) that are similar to GPE's butwith an addition of a second polymer such a poly(ethylene oxide), andliquid electrolytes (LE) such as a solvent mixture of ethylenecarbonate/diethyl carbonate with a lithium salt; and compositeorganic-inorganic electrolytes (CE), comprising an LE with an additionof titania, silica or other oxides. Some non-exclusive examples oflithium salts used are LiTFSI (lithium bis(trifluoromethane)sulfonimide), LiBF₄ (lithium tetrafluoroborate), LiPF₆ (lithiumhexafluorophosphate), LiAsF₆ (lithium hexafluoro arsenate), LiCF₃SO₃(lithium trifluoromethane sulfonate), LiB(C₆F₅)₄ (lithiumperfluorotetraphenylboron) and LiClO₄ (lithium perchlorate). Additionalexamples of suitable ion conductor layers include silicates, tungstenoxides, tantalum oxides, niobium oxides, and borates. The silicon oxidesinclude silicon-aluminum-oxide. These materials may be doped withdifferent dopants, including lithium. Lithium doped silicon oxidesinclude lithium silicon-aluminum-oxide. In some embodiments, the ionconductor layer comprises a silicate-based structure. In otherembodiments, suitable ion conductors particularly adapted for lithiumion transport include, but are not limited to, lithium silicate, lithiumaluminum silicate, lithium aluminum borate, lithium aluminum fluoride,lithium borate, lithium nitride, lithium zirconium silicate, lithiumniobate, lithium borosilicate, lithium phosphosilicate, and other suchlithium-based ceramic materials, silicas, or silicon oxides, includinglithium silicon-oxide.

The thickness of the ion conductor layer 10 will vary depending on thematerial. In some embodiments using an inorganic ion conductor the ionconductor layer 10 is about 250 nm to 1 nm thick, preferably about 50 nmto 5 nm thick. In some embodiments using an organic ion conductor, theion conductor layer is about 1000000 nm to 1000 nm thick or about 250000nm to 10000 nm thick. The thickness of the ion conductor layer is alsosubstantially uniform. In one embodiment, a substantially uniform ionconductor layer varies by not more than about +/−10% in each of theaforementioned thickness ranges. In another embodiment, a substantiallyuniform ion conductor layer varies by not more than about +/−5% in eachof the aforementioned thickness ranges. In another embodiment, asubstantially uniform ion conductor layer varies by not more than about+/−3% in each of the aforementioned thickness ranges.

Anode layer 20 is an electrochromic layer comprising lithium, nickel,and at least one bleached state stabilizing element as described ingreater detail elsewhere herein. In one embodiment, cathode layer 21 isan electrochromic layer. For example, cathode layer 21 may comprise anelectrochromic oxide based on tungsten, molybdenum, niobium, titanium,and/or bismuth. In an alternative embodiment, cathode layer 21 is anon-electrochromic counter-electrode for anode layer 20 such as ceriumoxide.

The thickness of anode layer 20 and cathode layer 21 will depend uponthe electrochromic material selected for the electrochromic layer andthe application. In some embodiments, anode layer 20 will have athickness in the range of about 25 nm to about 2000 nm. For example, inone embodiment anode layer 20 has a thickness of about 50 nm to about2000 nm. By way of further example, in one embodiment anode layer 20 hasa thickness of about 25 nm to about 1000 nm. By way of further example,in one such embodiment, anode layer 20 has an average thickness betweenabout 100 nm and about 700 nm. In some embodiments, anode layer 20 has athickness of about 250 nm to about 500 nm. Cathode layer 21 willtypically have thicknesses in the same ranges as those stated for anodelayer 20. One of skill in the art will appreciate that certainrelationships exist between the thickness of the anode or cathode layer,and the materials deposited to comprise the anode or cathode layer. Forexample, if the average thickness of the anode or cathode layer isbetween about 250 nm to about 500 nm, then anode or cathode precursormaterials that comprise the liquid mixtures used to deposit the anode orcathode layers will likely be composed of species that are smaller than250 nm to 500 nm.

In one embodiment, anode layer 20 and cathode layer 21 are inelectrochemically and optically matched (EOM) states. For example, whenthe cathode is a W-oxide film having a thickness of about 400 nm and anarea charge capacity of 27 mC/cm², the anode may be a lithium tungstennickel oxide film having a thickness of about 250 nm and a chargecapacity of 27 mC/cm² over a cell voltage of about 1.7V (where 0V is thefully bleached state of both anode and cathode).

Electrically conductive layer 22 is in electrical contact with oneterminal of a power supply (not shown) via bus bar 26 and electricallyconductive layer 23 is in electrical contact with the other terminal ofa power supply (not shown) via bus bar 27 whereby the transmissivity ofelectrochromic device 10 may be changed by applying a voltage pulse toelectrically conductive layers 22 and 23. The pulse causes electrons andions to move between anode layer 20 and cathode layer 21 and, as aresult, the anode layer 20 and, optionally, cathode layer 21 change(s)optical states, thereby switching electrochromic structure 1 from a moretransmissive state to a less transmissive state, or from a lesstransmissive state to a more transmissive state. In one embodiment,electrochromic structure 1 is transparent before the voltage pulse andless transmissive (e.g., more reflective or colored) after the voltagepulse or vice versa.

Referring again to FIG. 1, the power supply (not shown) connected to busbars 26, 27 is typically a voltage source with optional current limitsor current control features and may be configured to operate inconjunction with local thermal, photosensitive or other environmentalsensors. The voltage source may also be configured to interface with anenergy management system, such as a computer system that controls theelectrochromic device according to factors such as the time of year,time of day, and measured environmental conditions. Such an energymanagement system, in conjunction with large area electrochromic devices(e.g., an electrochromic architectural window), can dramatically lowerthe energy consumption of a building.

At least one of the substrates 24, 25 is preferably transparent, inorder to reveal the electrochromic properties of the stack 28 to thesurroundings. Any material having suitable optical, electrical, thermal,and mechanical properties may be used as first substrate 24 or secondsubstrate 25. Such substrates include, for example, glass, plastic,metal, and metal coated glass or plastic. Non-exclusive examples ofpossible plastic substrates are polycarbonates, polyacrylics,polyurethanes, urethane carbonate copolymers, polysulfones, polyimides,polyacrylates, polyethers, polyester, polyethylenes, polyalkenes,polyimides, polysulfides, polyvinylacetates and cellulose-basedpolymers. If a plastic substrate is used, it may be barrier protectedand abrasion protected using a hard coat of, for example, a diamond-likeprotective coating, a silica/silicone anti-abrasion coating, or thelike, such as is well known in the plastic glazing art. Suitable glassesinclude either clear or tinted soda lime glass, chemically tempered sodalime glass, heat strengthened soda lime glass, tempered glass, orborosilicate glass. In some embodiments of electrochromic structure 1with glass, e.g. soda lime glass, used as first substrate 24 and/orsecond substrate 25, there is a sodium diffusion barrier layer (notshown) between first substrate 24 and first electrically conductivelayer 22 and/or between second substrate 25 and second electricallyconductive layer 23 to prevent the diffusion of sodium ions from theglass into first and/or second electrically conductive layer 23. In someembodiments, second substrate 25 is omitted.

In one preferred embodiment of the disclosure, first substrate 24 andsecond substrate 25 are each float glass. In certain embodiments forarchitectural applications, this glass is at least 0.5 meters by 0.5meters, and can be much larger, e.g., as large as about 3 meters by 4meters. In such applications, this glass is typically at least about 2mm thick and more commonly 4-6 mm thick.

Independent of application, the electrochromic structures of the presentdisclosure may have a wide range of sizes. In general, it is preferredthat the electrochromic structure comprise a substrate having a surfacewith a surface area of at least 0.001 meter². For example, in certainembodiments, the electrochromic structure comprises a substrate having asurface with a surface area of at least 0.01 meter². By way of furtherexample, in certain embodiments, the electrochromic structure comprisesa substrate having a surface with a surface area of at least 0.1 meter².By way of further example, in certain embodiments, the electrochromicstructure comprises a substrate having a surface with a surface area ofat least 1 meter². By way of further example, in certain embodiments,the electrochromic structure comprises a substrate having a surface witha surface area of at least 5 meter². By way of further example, incertain embodiments, the electrochromic structure comprises a substratehaving a surface with a surface area of at least 10 meter².

At least one of the two electrically conductive layers 22, 23 is alsopreferably transparent in order to reveal the electrochromic propertiesof the stack 28 to the surroundings. In one embodiment, electricallyconductive layer 23 is transparent. In another embodiment, electricallyconductive layer 22 is transparent. In another embodiment, electricallyconductive layers 22, 23 are each transparent. In certain embodiments,one or both of the electrically conductive layers 22, 23 is inorganicand/or solid. Electrically conductive layers 22 and 23 may be made froma number of different transparent materials, including transparentconductive oxides, thin metallic coatings, networks of conductivenanoparticles (e.g., rods, tubes, dots) conductive metal nitrides, andcomposite conductors. Transparent conductive oxides include metal oxidesand metal oxides doped with one or more metals. Examples of such metaloxides and doped metal oxides include indium oxide, indium tin oxide,doped indium oxide, tin oxide, doped tin oxide, zinc oxide, aluminumzinc oxide, doped zinc oxide, ruthenium oxide, doped ruthenium oxide andthe like. Transparent conductive oxides are sometimes referred to as(TCO) layers. Thin metallic coatings that are substantially transparentmay also be used. Examples of metals used for such thin metalliccoatings include gold, platinum, silver, aluminum, nickel, and alloys ofthese. Examples of transparent conductive nitrides include titaniumnitrides, tantalum nitrides, titanium oxynitrides, and tantalumoxynitrides. Electrically conducting layers 22 and 23 may also betransparent composite conductors. Such composite conductors may befabricated by placing highly conductive ceramic and metal wires orconductive layer patterns on one of the faces of the substrate and thenover-coating with transparent conductive materials such as doped tinoxides or indium tin oxide. Ideally, such wires should be thin enough asto be invisible to the naked eye (e.g., about 100 μm or thinner).Non-exclusive examples of electron conductors 22 and 23 transparent tovisible light are thin films of indium tin oxide (ITO), tin oxide, zincoxide, titanium oxide, n- or p-doped zinc oxide and zinc oxyfluoride.Metal-based layers, such as ZnS/Ag/ZnS and carbon nanotube layers havebeen recently explored as well. Depending on the particular application,one or both electrically conductive layers 22 and 23 may be made of orinclude a metal grid.

The thickness of the electrically conductive layer may be influenced bythe composition of the material comprised within the layer and itstransparent character. In some embodiments, electrically conductivelayers 22 and 23 are transparent and each have a thickness that isbetween about 1000 nm and about 50 nm. In some embodiments, thethickness of electrically conductive layers 22 and 23 is between about500 nm and about 100 nm. In other embodiments, the electricallyconductive layers 22 and 23 each have a thickness that is between about400 nm and about 200 nm. In general, thicker or thinner layers may beemployed so long as they provide the necessary electrical properties(e.g., conductivity) and optical properties (e.g., transmittance). Forcertain applications it will generally be preferred that electricallyconductive layers 22 and 23 be as thin as possible to increasetransparency and to reduce cost.

Referring again to FIG. 1, the function of the electrically conductivelayers is to apply the electric potential provided by a power supplyover the entire surface of the electrochromic stack 28 to interiorregions of the stack. The electric potential is transferred to theconductive layers though electrical connections to the conductivelayers. In some embodiments, bus bars, one in contact with firstelectrically conductive layer 22 and one in contact with secondelectrically conductive layer 23 provide the electrical connectionbetween the voltage source and the electrically conductive layers 22 and23.

In one embodiment, the sheet resistance, R_(s), of the first and secondelectrically conductive layers 22 and 23 is about 500Ω/□ to 1Ω/□. Insome embodiments, the sheet resistance of first and second electricallyconductive layers 22 and 23 is about 100Ω/□ to 5Ω/□. In general, it isdesirable that the sheet resistance of each of the first and secondelectrically conductive layers 22 and 23 be about the same. In oneembodiment, first and second electrically conductive layers 22 and 23each have a sheet resistance of about 20Ω/□ to about 8Ω/□.

To facilitate more rapid switching of electrochromic structure 1 from astate of relatively greater transmittance to a state of relativelylesser transmittance, or vice versa, at least one of electricallyconductive layers 22, 23 may have a sheet resistance, R_(s), to the flowof electrons through the layer that is non-uniform. For example, in oneembodiment only one of first and second electrically conductive layers22, 23 has a non-uniform sheet resistance to the flow of electronsthrough the layer. Alternatively, first electrically conductive layer 22and second electrically conductive layer 23 may each have a non-uniformsheet resistance to the flow of electrons through the respective layers.Without being bound by any particular theory, it is presently believedthat spatially varying the sheet resistance of electrically conductivelayer 22, spatially varying the sheet resistance of electricallyconductive layer 23, or spatially varying the sheet resistance ofelectrically conductive layer 22 and electrically conductive layer 23improves the switching performance of the device by controlling thevoltage drop in the conductive layer to provide a uniform potential dropor a desired non-uniform potential drop across the device, over the areaof the device as more fully described in WO2012/109494.

FIG. 2 depicts a cross-sectional structural diagram of electrochromicstructure 1 according to an alternative embodiment of the presentdisclosure. Moving outward from the center, electrochromic structure 1comprises an ion conductor layer 10. Anode electrode layer 20 (anelectrochromic layer comprising lithium, nickel, and at least onebleached state stabilizing element as described in greater detailelsewhere herein) is on one side of and in contact with a first surfaceof ion conductor layer 10, and cathode layer 21 is on the other side ofand in contact with a second surface of ion conductor layer 10. Firstand second current modulating structures 30 and 31, in turn, areadjacent first and second electrically conductive layers 22 and 23,respectively, which are arranged against outer substrates 24, 25,respectively.

To facilitate more rapid switching of electrochromic structure 1 from astate of relatively greater transmittance to a state of relativelylesser transmittance, or vice versa, first current modulating structure30, second current modulating structure 31 or both first and secondcurrent modulating structures 30 and 31 comprise a resistive material(e.g., a material having a resistivity of at least about 10⁴Ω·cm). Inone embodiment at least one of first and second current modulatingstructures 30, 31 has a non-uniform cross-layer resistance, R_(C), tothe flow of electrons through the structure. In one such embodiment onlyone of first and second current modulating structures 30, 31 has anon-uniform cross-layer resistance, R_(C), to the flow of electronsthrough the layer. Alternatively, and more typically, first currentmodulating structure 30 and second current modulating structure 31 eachhave a non-uniform cross-layer resistance, R_(C), to the flow ofelectrons through the respective layers. Without being bound by anyparticular theory, it is presently believed that spatially varying thecross-layer resistance, R_(C), of first current modulating structure 30and second current modulating structure 31, spatially varying thecross-layer resistance, R_(C), of the first current modulating structure30, or spatially varying the cross-layer resistance, R_(C), of thesecond current modulating structure 31 improves the switchingperformance of the device by providing a more uniform potential drop ora desired non-uniform potential drop across the device, over the area ofthe device.

In one exemplary embodiment, current modulating structure 30 and/or 31is a composite comprising at least two materials possessing differentconductivities. For example, in one embodiment the first material is aresistive material having a resistivity in the range of about 10⁴Ω·cm to10¹⁰Ω·cm and the second material is an insulator. By way of furtherexample, in one embodiment the first material is a resistive materialhaving a resistivity of at least 10⁴Ω·cm and the second material has aresistivity that exceeds the resistivity of the first by a factor of atleast 10². By way of further example, in one embodiment the firstmaterial is a resistive material having a resistivity of at least10⁴Ω·cm and the second material has a resistivity that exceeds theresistivity of the first by a factor of at least 10³. By way of furtherexample, in one embodiment the first material is a resistive materialhaving a resistivity of at least 10⁴Ω·cm and the second material has aresistivity that exceeds the resistivity of the first by a factor of atleast 10⁴. By way of further example, in one embodiment the firstmaterial is a resistive material having a resistivity of at least10⁴Ω·cm and the second material has a resistivity that exceeds theresistivity of the first by a factor of at least 10⁵. By way of furtherexample, in one embodiment, at least one of current modulatingstructures 30, 31 comprises a first material having a resistivity in therange of 10⁴ to 10¹⁰Ω·cm and a second material that is an insulator orhas a resistivity in the range of 10¹⁰ to 10¹⁴Ω·cm. By way of furtherexample, in one embodiment, at least one of current modulatingstructures 30, 31 comprises a first material having a resistivity in therange of 10⁴ to 10¹⁰Ω·cm and a second material having a resistivity inthe range of 10¹⁰ to 10¹⁴Ω·cm wherein the resistivities of the first andsecond materials differ by a factor of at least 10³. By whay of furtherexample, in one embodiment, at least one of current modulatingstructures 30, 31 comprises a first material having a resistivity in therange of 10⁴ to 10¹⁰Ω ·cm and a second material having a resistivity inthe range of 10¹⁰ to 10¹⁴Ω·cm wherein the resistivities of the first andsecond materials differ by a factor of at least 10⁴. By way of furtherexample, in one embodiment, at least one of current modulatingstructures 30, 31 comprises a first material having a resistivity in therange of 10⁴ to 10¹⁰Ω ·cm and a second material having a resistivity inthe range of 10¹⁰ to 10¹⁴Ω·cm wherein the resistivities of the first andsecond materials differ by a factor of at least 10⁵. In each of theforegoing exemplary embodiments, each of current modulating structures30, 31 may comprise a first material having a resistivity in the rangeof 10⁴ to 10¹⁰Ω ·cm and a second material that is insulating.

Depending upon the application, the relative proportions of the firstand second materials in current modulating structure 30 and/or 31 mayvary substantially. In general, however, the second material (i.e., theinsulating material or material having a resistivity of at least 10¹⁰Ω·cm) constitutes at least about 5 vol % of at least one of currentmodulating structures 30, 31. For example, in one embodiment the secondmaterial constitutes at least about 10 vol % of at least one of currentmodulating structures 30, 31. By way of further example, in oneembodiment the second material constitutes at least about 20 vol % of atleast one of current modulating structures 30, 31. By way of furtherexample, in one embodiment the second material constitutes at leastabout 30 vol % of at least one of current modulating structures 30, 31.By way of further example, in one embodiment the second materialconstitutes at least about 40 vol % of at least one of currentmodulating structures 30, 31. In general, however, the second materialwill typically not constitute more than about 70 vol % of either ofcurrent modulating structures 30, 31. In each of the foregoingembodiments and as previously discussed, the second material may have aresistivity in the range of 10¹⁰ to 10¹⁴Ω·cm and the resistivities ofthe first and second materials (in either or both of current modulatingstructures 30, 31) may differ by a factor of at least 10³.

In general, first and second current modulating structures 30, 31 maycomprise any material exhibiting sufficient resistivity, opticaltransparency, and chemical stability for the intended application. Forexample, in some embodiments, current modulating structures 30, 31 maycomprise a resistive or insulating material with high chemicalstability. Exemplary insulator materials include alumina, silica, poroussilica, fluorine doped silica, carbon doped silica, silicon nitride,silicon oxynitride, hafnia, magnesium fluoride, magnesium oxide,poly(methyl methacrylate) (PMMA), polyimides, polymeric dielectrics suchas polytetrafluoroethylene (PTFE) and silicones. Exemplary resistivematerials include zinc oxide, zinc sulfide, titanium oxide, and gallium(III) oxide, yttrium oxide, zirconium oxide, aluminum oxide, indiumoxide, stannic oxide and germanium oxide. In one embodiment, one or bothof first and second current modulating structures 30, 31 comprise one ormore of such resistive materials. In another embodiment, one or both offirst and second current modulating structures 30, 31 comprise one ormore of such insulating materials. In another embodiment, one or both offirst and second current modulating structures 30, 31 comprise one ormore of such resistive materials and one or more of such insulatingmaterials.

The thickness of current modulating structures 30, 31 may be influencedby the composition of the material comprised by the structures and itsresistivity and transmissivity. In some embodiments, current modulatingstructures 30 and 31 are transparent and each have a thickness that isbetween about 50 nm and about 1 micrometer. In some embodiments, thethickness of current modulating structures 30 and 31 is between about100 nm and about 500 nm. In general, thicker or thinner layers may beemployed so long as they provide the necessary electrical properties(e.g., conductivity) and optical properties (e.g., transmittance). Forcertain applications it will generally be preferred that currentmodulating structures 30 and 31 be as thin as possible to increasetransparency and to reduce cost.

Liquid Mixtures

Anodic electrochromic layers comprising lithium nickel oxidecompositions may be prepared, in accordance with one aspect of thepresent disclosure from a liquid mixture containing lithium, nickel, andat least one bleached state stabilizing element selected from the groupconsisting of Group 3, Group 4, Group 5, Group 6, Group 13, Group 14 andGroup 15 elements, and combinations thereof. For example, in oneembodiment, the liquid mixture is deposited on the surface of asubstrate to form a film comprising lithium, nickel, and at least onesuch bleached state stabilizing element and the deposited film is thentreated to form an anodic electrochromic layer containing lithium,nickel and the bleached state stabilizing element(s).

The liquid mixture deposited onto the substrate surface comprises acontinuous (liquid) phase and a discontinuous phase comprising adispersed species. In general, the dispersed species has a (number)average size greater than 5 nm. For example, in some embodiments thedispersed species has a (number) average size greater than 10 nm. By wayof further example, in some embodiments the dispersed species has a(number) average size greater than 25 nm. By way of further example, insome embodiments the dispersed species has a (number) average sizegreater than 50 nm. By way of further example, in some embodiments thedispersed species has a (number) average size greater than 75 nm. By wayof further example, in some embodiments the dispersed species has a(number) average size greater than 100 nm. In general, however, thedispersed species has a (number) average size that is less than 200 nm.For example, in some embodiments the dispersed species has a (number)average size less than 150 nm. By way of further example, in someembodiments the dispersed species has a (number) average size less than125 nm. By way of further example, in some embodiments the dispersedspecies has a (number) average size less than 100 nm. By way of furtherexample, in some embodiments the dispersed species has a (number)average size in the range of 10 nm to 50 nm (e.g., 25 nm-50 nm) or a(number) average size in the range of 50 nm-100 nm (e.g., 50 nm-80 nm).Dependent upon the methodology used to prepare the dispersion, thedispersed species may comprise discrete particles such as metal oxideparticles, metal hydroxide particles, metal alkoxide particles, metalalkoxide oligomers, gels or particles, or a combination thereof, each ofwhich may independently possess any of the aforementioned average sizesor fall within any of the aforementioned size ranges.

In one embodiment, the relative amounts of lithium, nickel and thebleached state stabilizing element(s) in the liquid mixture arecontrolled such that an atomic ratio of lithium to the combined amountof nickel and bleached state stabilizing element(s) in the depositedfilm is generally at least about 0.4:1, respectively. For example, inone such embodiment, the atomic ratio of lithium to the combined amountof nickel and bleached state stabilizing element(s) M in the liquidmixture is at least about 0.4:1 (Li:[Ni+M]), respectively, wherein M isa bleached state stabilizing element selected from the group consistingof Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, Sb andcombinations thereof; stated differently, the atomic ratio of the amountof lithium to the combined amount of Ni, Y, Ti, Zr, Hf, V, Nb, Ta, Mo,W, B, Al, Ga, In, Si, Ge, Sn, and Sb, in the liquid mixture is at least0.4:1 (Li:[Ni+M]). By way of further example, in one such embodiment theatomic ratio of lithium to the combined amount of nickel and allbleached state stabilizing element(s) M in the liquid mixture (e.g.,wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn,Sb or a combination thereof) is at least about 0.75:1, respectively. Byway of further example, in one such embodiment the atomic ratio oflithium to the combined amount of nickel and all bleached statestabilizing element(s) M in the liquid mixture (e.g., wherein M is Y,Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, Sb or acombination thereof) is at least about 0.9:1, respectively. By way offurther example, in one such embodiment the atomic ratio of lithium tothe combined amount of nickel and all bleached state stabilizingelement(s) M in the liquid mixture (e.g., wherein M is Y, Ti, Zr, Hf, V,Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, Sb or a combination thereof)is at least about 1:1, respectively. By way of further example, in onesuch embodiment the atomic ratio of lithium to the combined amount ofnickel and all bleached state stabilizing element(s) M in the liquidmixture (e.g., wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga,In, Si, Ge, Sn, Sb or a combination thereof) is at least about 1.25:1,respectively. By way of further example, in one such embodiment theatomic ratio of lithium to the combined amount of nickel and allbleached state stabilizing element(s) M in the liquid mixture (e.g.,wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn,Sb or a combination thereof) is at least about 1.5:1, respectively. Byway of further example, in one such embodiment the atomic ratio oflithium to the combined amount of nickel and all bleached statestabilizing element(s) M in the liquid mixture (e.g., wherein M is Y,Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, Sb or acombination thereof) is at least about 2:1, respectively. By way offurther example, in one such embodiment the atomic ratio of lithium tothe combined amount of nickel and all bleached state stabilizingelement(s) M in the liquid mixture (e.g., wherein M is Y, Ti, Zr, Hf, V,Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, Sb or a combination thereof)is at least about 2.5:1, respectively.

In certain embodiments, the atomic ratio of lithium to the combinedamount of nickel and all bleached state stabilizing element(s) M in theliquid mixture (e.g., wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B,Al, Ga, In, Si, Ge, Sn, Sb or a combination thereof) will not exceedabout 4:1, respectively. In some embodiments, therefore, the atomicratio of lithium to the combined amount of nickel and all bleached statestabilizing element(s) M in the liquid mixture (e.g., wherein M is Y,Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, Sb or acombination thereof) will be in the range about 0.75:1 to about 3:1,respectively. In some embodiments, therefore, the atomic ratio oflithium to the combined amount of nickel and all bleached statestabilizing element(s) M in the liquid mixture (e.g., wherein M is Y,Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, Sb or acombination thereof) will be in the range about 0.9:1 to about 2.5:1,respectively. In some embodiments, therefore, the atomic ratio oflithium to the combined amount of nickel and all bleached statestabilizing element(s) M in the liquid mixture (e.g., wherein M is Y,Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, Sb or acombination thereof) will be in the range about 1:1 to about 2.5:1,respectively. In some embodiments, therefore, the atomic ratio oflithium to the combined amount of nickel and all bleached statestabilizing element(s) M in the liquid mixture (e.g., wherein M is Y,Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, Sb or acombination thereof) will be in the range about 1.1:1 to about 1.5:1,respectively. In some embodiments, therefore, the atomic ratio oflithium to the combined amount of nickel and all bleached statestabilizing element(s) M in the liquid mixture (e.g., wherein M is Y,Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, Sb or acombination thereof) will be in the range about 1.5:1 to about 2:1,respectively. In some embodiments, therefore, the atomic ratio oflithium to the combined amount of nickel and all bleached statestabilizing element(s) M in the liquid mixture (e.g., wherein M is Y,Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, Sb or acombination thereof) will be in the range about 2:1 to about 2.5:1,respectively.

The atomic ratio of the relative amount of nickel and the bleached statestabilizing element(s) in the liquid mixture will typically be less thanabout 0.8:1 (M:[Ni+M]) wherein the bleached state stabilizing element(s)is/are selected from the group consisting of is Y, Ti, Zr, Hf, V, Nb,Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, Sb and combinations thereof. Thus,for example, in certain embodiments the atomic ratio of the combinedamount of all such bleached state stabilizing elements M to the combinedamount of nickel and the bleached state stabilizing elements M in theliquid mixture will be less than about 0.7:1. By way of further example,in one such embodiment the atomic ratio of the combined amount of allsuch bleached state stabilizing elements M (e.g., wherein M is Y, Ti,Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, Sb or a combinationthereof) to the combined amount of nickel and such bleached statestabilizing elements in the liquid mixture is less than about 0.6:1. Byway of further example, in one such embodiment the atomic ratio of thecombined amount of all such bleached state stabilizing elements M (e.g.,wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn,Sb or a combination thereof) to nickel and such bleached statestabilizing elements in the liquid mixture is less than about 0.5:1. Byway of further example, in one such embodiment the atomic ratio of thecombined amount of all such bleached state stabilizing elements M (e.g.,wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn,Sb or a combination thereof) to nickel and such bleached statestabilizing elements in the liquid mixture is less than about 0.4:1.

The atomic ratio of the relative amount of nickel and the bleached statestabilizing element(s) in the liquid mixture will typically be at leastabout 0.025:1 (M:[Ni+M]) wherein the bleached state stabilizingelement(s) is/are selected from the group consisting of is Y, Ti, Zr,Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, Sb and combinationsthereof. For example, in one such embodiment the atomic ratio of thecombined amount of all such bleached state stabilizing elements M (e.g.,wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn,Sb or a combination thereof) to the combined amount of nickel and suchbleached state stabilizing elements in the liquid mixture is greaterthan about 0.03:1. By way of further example, in one such embodiment theatomic ratio of the combined amount of all such bleached statestabilizing elements M (e.g., wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo,W, B, Al, Ga, In, Si, Ge, Sn, Sb or a combination thereof) to thecombined amount of nickel and such bleached state stabilizing elementsin the liquid mixture is greater than about 0.05:1. By way of furtherexample, in one such embodiment the atomic ratio of the combined amountof all such bleached state stabilizing elements M (e.g., wherein M is Y,Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, Sb or acombination thereof) to the combined amount of nickel and such bleachedstate stabilizing elements in the liquid mixture is greater than about0.075:1. By way of further example, in one such embodiment the atomicratio of the combined amount of all such bleached state stabilizingelements M (e.g., wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al,Ga, In, Si, Ge, Sn, Sb or a combination thereof) to the combined amountof nickel and such bleached state stabilizing elements in the liquidmixture is greater than about 0.1:1. By way of further example, in onesuch embodiment the atomic ratio of the combined amount of all suchbleached state stabilizing elements M (e.g., wherein M is Y, Ti, Zr, Hf,V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, Sb or a combinationthereof) to the combined amount of nickel and such bleached statestabilizing elements in the liquid mixture is greater than about 0.15:1.By way of further example, in one such embodiment the atomic ratio ofthe combined amount of all such bleached state stabilizing elements M(e.g., wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si,Ge, Sn, Sb or a combination thereof) to the combined amount of nickeland such bleached state stabilizing elements in the liquid mixture isgreater than about 0.25:1. In each of the foregoing embodiments, theelement(s) M may be selected from a more limited set of bleached statestabilizing elements. For example, in each of the foregoing embodiments,the bleached state stabilizing element may be selected from the groupconsisting of Y, Ti, Zr, Hf, Nb, Ta, Mo, W, B, Al, Ga, In, Si, andcombinations thereof. By way of further example, in each of theforegoing embodiments, the bleached state stabilizing element may beselected from the group consisting of Y, Ti, Zr, Hf, Nb, Ta, Mo, W, B,Al, Ga, In, and combinations thereof. By way of further example, in eachof the foregoing embodiments, the bleached state stabilizing element maybe selected from the group consisting of Y, Ti, Zr, Hf, Nb, Ta, Mo, W,and combinations thereof. By way of further example, in each of theforegoing embodiments, the bleached state stabilizing element may beselected from the group consisting of Ti, Zr, Hf, Nb, Ta, Mo, W, andcombinations thereof. By way of further example, in each of theforegoing embodiments, the bleached state stabilizing element may beselected from the group consisting of Ti, Zr, Hf and combinationsthereof. By way of further example, in each of the foregoingembodiments, the bleached state stabilizing element may be selected fromthe group consisting of Zr, Hf, and a combination thereof. By way offurther example, in each of the foregoing embodiments, the bleachedstate stabilizing element may be selected from the group consisting ofNb, Ta, and a combination thereof. By way of further example, in each ofthe foregoing embodiments, the bleached state stabilizing element may beTi. By way of further example, in each of the foregoing embodiments, thebleached state stabilizing element may be Zr. By way of further example,in each of the foregoing embodiments, the bleached state stabilizingelement may be Hf. By way of further example, in each of the foregoingembodiments, the bleached state stabilizing element may be Nb. By way offurther example, in each of the foregoing embodiments, the bleachedstate stabilizing element may be Ta. By way of further example, in eachof the foregoing embodiments, the bleached state stabilizing element maybe Mo. By way of further example, in each of the foregoing embodiments,the bleached state stabilizing element may be W. By way of furtherexample, in each of the foregoing embodiments, the bleached statestabilizing element may be B. By way of further example, in each of theforegoing embodiments, the bleached state stabilizing element may be Al.By way of further example, in each of the foregoing embodiments, thebleached state stabilizing element may be Ga. By way of further example,in each of the foregoing embodiments, the bleached state stabilizingelement may be In. By way of further example, in each of the foregoingembodiments, the bleached state stabilizing element may be Si. By way offurther example, in each of the foregoing embodiments, the bleachedstate stabilizing element may be Ge. By way of further example, in eachof the foregoing embodiments, the bleached state stabilizing element maybe Sn. By way of further example, in each of the foregoing embodiments,the bleached state stabilizing element may be Sb. By way of furtherexample, in each of the foregoing embodiments, the bleached statestabilizing element may be selected from the group consisting of Mo andW and a combination thereof. By way of further example, in each of theforegoing embodiments, the bleached state stabilizing element may beselected from the group consisting of Ti, Zr, Hf, Ta, Nb, W andcombinations thereof.

The atomic ratio of the relative amount of nickel and the bleached statestabilizing element(s) in the liquid mixture will typically be in therange of about 0.025:1 to about 0.8:1 (M:[Ni+M]) wherein the bleachedstate stabilizing element(s) is/are selected from the group consistingof is Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, Sb andcombinations thereof. For example, in one such embodiment the atomicratio of the combined amount of all such bleached state stabilizingelement(s) M (e.g., wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al,Ga, In, Si, Ge, Sn, Sb or a combination thereof) to the combined amountof nickel and such bleached state stabilizing elements in the liquidmixture is between about 0.04:1 and about 0.75:1 (M:[Ni+M]). By way offurther example, in one such embodiment the atomic ratio of the combinedamount of all such bleached state stabilizing element(s) M (e.g.,wherein M is Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn,Sb or a combination thereof) to the combined amount of nickel and suchbleached state stabilizing elements in the liquid mixture is betweenabout 0.05:1 and about 0.65:1 (M:[Ni+M]). By way of further example, inone such embodiment the atomic ratio of the combined amount of all suchbleached state stabilizing element(s) M (e.g., wherein M is Y, Ti, Zr,Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, Sb or a combinationthereof) to the combined amount of nickel and such bleached statestabilizing elements in the liquid mixture is between about 0.1:1 andabout 0.6:1 (M:[Ni+M]). In each of the foregoing embodiments, theelement(s) M may be selected from a more limited set of bleached statestabilizing elements. For example, in each of the foregoing embodiments,the bleached state stabilizing element may be selected from the groupconsisting of Y, Ti, Zr, Hf, Nb, Ta, Mo, W, B, Al, Ga, In, Si, andcombinations thereof. By way of further example, in each of theforegoing embodiments, the bleached state stabilizing element may beselected from the group consisting of Y, Ti, Zr, Hf, Nb, Ta, Mo, W, B,Al, Ga, In, and combinations thereof. By way of further example, in eachof the foregoing embodiments, the bleached state stabilizing element maybe selected from the group consisting of Y, Ti, Zr, Hf, Nb, Ta, Mo, W,and combinations thereof. By way of further example, in each of theforegoing embodiments, the bleached state stabilizing element may beselected from the group consisting of Ti, Zr, Hf, Nb, Ta, Mo, W, andcombinations thereof. By way of further example, in each of theforegoing embodiments, the bleached state stabilizing element may beselected from the group consisting of Ti, Zr, Hf and combinationsthereof. By way of further example, in each of the foregoingembodiments, the bleached state stabilizing element may be selected fromthe group consisting of Zr, Hf, and a combination thereof. By way offurther example, in each of the foregoing embodiments, the bleachedstate stabilizing element may be selected from the group consisting ofNb, Ta, and a combination thereof. By way of further example, in each ofthe foregoing embodiments, the bleached state stabilizing element may beTi. By way of further example, in each of the foregoing embodiments, thebleached state stabilizing element may be Zr. By way of further example,in each of the foregoing embodiments, the bleached state stabilizingelement may be Hf. By way of further example, in each of the foregoingembodiments, the bleached state stabilizing element may be Nb. By way offurther example, in each of the foregoing embodiments, the bleachedstate stabilizing element may be Ta. By way of further example, in eachof the foregoing embodiments, the bleached state stabilizing element maybe Mo. By way of further example, in each of the foregoing embodiments,the bleached state stabilizing element may be W. By way of furtherexample, in each of the foregoing embodiments, the bleached statestabilizing element may be B. By way of further example, in each of theforegoing embodiments, the bleached state stabilizing element may be Al.By way of further example, in each of the foregoing embodiments, thebleached state stabilizing element may be Ga. By way of further example,in each of the foregoing embodiments, the bleached state stabilizingelement may be In. By way of further example, in each of the foregoingembodiments, the bleached state stabilizing element may be Si. By way offurther example, in each of the foregoing embodiments, the bleachedstate stabilizing element may be Ge. By way of further example, in eachof the foregoing embodiments, the bleached state stabilizing element maybe Sn. By way of further example, in each of the foregoing embodiments,the bleached state stabilizing element may be Sb. By way of furtherexample, in each of the foregoing embodiments, the bleached statestabilizing element may be selected from the group consisting of Mo andW and a combination thereof. By way of further example, in each of theforegoing embodiments, the bleached state stabilizing element may beselected from the group consisting of Ti, Zr, Hf, Ta, Nb, W andcombinations thereof.

The liquid mixture is prepared by combining, in a solvent system, asource of lithium, nickel, and at least one bleached state stabilizingelement. In general, the source (starting) materials for each of thelithium, nickel and bleached state stabilizing element composition(s)comprised by the liquid mixture are soluble or dispersible in the liquidmixture solvent system and provide a source of metal(s) or metal oxide(s) for the lithium nickel oxide film. Additionally, at least one oflithium, nickel and bleached state stabilizing element source (starting)materials is a hydrolysable composition capable of polycondensation.

The lithium component of the liquid mixture may be derived from a rangeof soluble or dispersible lithium-containing source (starting) materialsthat chemically or thermally decompose to provide a source of lithium.For example, the source of lithium for the liquid mixture may comprise alithium derivative of an organic compound (e.g., an organo-lithiumcompound) or a lithium salt of an organic or inorganic anion such asacetate, hydroxide, carbonate, nitrate, sulfate, peroxide, bicarbonateand the like. In certain embodiments, lithium acetate is sometimespreferred.

A wide variety of lithium derivatives of organic compounds are describedin the literature and are useful as lithium sources for the liquidmixtures of this disclosure. They include lithium derivatives of alkanes(alkyl lithium compounds), aromatic compounds (aryl lithium compounds),olefins (vinyl or allyl lithium compounds), acetylenes (lithiumacetylide compounds), alcohols (lithium alkoxide compounds), amines,(lithium amide compounds), thiols (lithium thiolate compounds),carboxylic acids (lithium carboxylate compounds) and β-diketones(β-diketonate compounds). Since the role of the lithium compound is toprovide a soluble source of lithium ion in the lithium nickel oxidelayer, the organic portion of the organo-lithium compound is removedduring processing; it is preferred to utilize simple, low cost, andreadily available organo-lithium compounds. It is further preferred thatthe organo-lithium compound be one that is not pyrophoric when exposedto air; this property limits but does not exclude the use of alkyl,aryl, vinyl, allyl, acetylide organo-lithium reagents as lithium sourcesin the liquid mixtures of this disclosure. In one embodiment, the source(starting) material for the lithium component of the liquid mixture is alithium amide compound corresponding to the formula LiNR¹R² wherein R¹and R² are hydrocarbyl, substituted hydrocarbyl, or silyl, andoptionally, R¹ and R² and the nitrogen atom to which they are bonded mayform a heterocycle.

In one embodiment, the source (starting) material for the lithiumcomponent of the liquid mixture is a lithium alkoxide corresponding tothe formula LiOR wherein R is hydrocarbyl, substituted hydrocarbyl, oroptionally substituted silyl. In one such embodiment, the source(starting) material for the lithium component of the liquid mixture is alithium alkoxide corresponding to the formula LiOR wherein R isoptionally substituted alkyl or aryl. For example, in one suchembodiment, R is linear, branched or cyclic alkyl. By way of furtherexample, in one such embodiment, R is 2-dimethylaminoethyl. By way offurther example, in one such embodiment, R is 2-methoxyethyl. By way offurther example, in one such embodiment, R is optionally substitutedaryl. In another embodiment, the source (starting) material for thelithium component of the liquid mixture is a lithium carboxylatecorresponding to the formula LiOC(O)R¹ wherein R¹ is hydrogen,hydrocarbyl, substituted hydrocarbyl, heterocyclo or optionallysubstituted silyl. For example, in one such embodiment R¹ is methyl(lithium acetate). By way of further example, in one such embodiment, R¹is a linear or branched alkyl. By way of further example, in one suchembodiment, R¹ is cyclic or polycyclic. By way of further example, inone such embodiment, R¹ is optionally substituted aryl.

In another embodiment, the source (starting) material for the lithiumcomponent of the liquid mixture is a lithium β-diketonate correspondingto the formula

wherein R¹⁰ and R¹¹ are independently hydrocarbyl, substitutedhydrocarbyl, or optionally substituted silyl. For example, in one suchembodiment, R¹⁰ and R¹¹ are independently linear or branched alkyl. Byway of further example, in one such embodiment, R¹⁰ and R¹¹ areindependently cyclic or polycyclic.

As previously noted, in one embodiment, the source (starting) materialfor the lithium component of the liquid mixture comprises hydrolysablelithium compositions. Hydrolysable lithium precursors are readilysoluble in a variety of solvents including common organic solvents andreact with atmospheric or intentionally added water liberating theanionic ligand in its protonated form (e.g., X—H). The ligand impartssolubility in organic solvents such as aliphatic and aromatichydrocarbons, ethers, and alcohols and generally affects the reactivityof the lithium complex. Preferred hydrolysable lithium precursors areprepared using Li-complexes that are stabilized by substituted alkoxideligands derived from alcohols of the following general formulaeHOC(R₃)(R₄)C(R₅)(R₆)(R₇)wherein R₃, R₄, R₅, R₆, and R₇ are independently substituted orunsubstituted hydrocarbyl groups, at least one of R₃, R₄, R₅, R₆, and R₇comprises an electronegative heteroatom, and where any of R₃, R₄, R₅,R₆, and R₇ can be joined together to form a ring. The preferredelectronegative heteroatoms are oxygen or nitrogen. Preferred alkoxideligands [—OC(R₃)(R₄)C(R₅)(R₆)(R₇)] are derived from alcohols in whichone or more R₅, R₆, and R₇ is an ether or amine functional group. Anexemplary alkoxide ligand is the one derived from1-dimethylamino-2-propanol (DMAP): HOCH(Me)CH₂NMe₂.

In one embodiment, the source (starting) material for the lithiumcomponent of the liquid mixture comprises a lithium salt of an anioncontaining nickel or a bleached state-stabilizing element. For example,in one such embodiment, the source (starting) material for the lithiumcomponent of the liquid mixture comprises a lithium salt of aniso-polyoxometallate or a heteropolyoxometalate. A heteropolyoxometalateis a metal oxide cluster that surrounds a central heteroatom([X_(x)M_(m)O_(y)]^(q-) where X is the heteroatom and M is commonly butnot only W or Mo, e.g. [PMo₁₂O₄₀]³⁻). An isopolyoxometalate is a metaloxide cluster that contains no central heteroatom ([M_(m)O_(y)]^(q-)where M has been reported to be V, Nb, Ta, Cr, Mo, W and others, e.g.[W₄O₁₆]⁸⁻). Alternatively, in one such embodiment, the source (starting)material for the lithium component of the liquid mixture comprises alithium salt, or an adduct of a lithium salt such as an etherate of alithium salt, of an anionic coordination complex of nickel and/or ableached state stabilizing element. For example, in one such embodiment,the lithium salt is a lithium salt of a coordination complexcorresponding to the formula [M⁴(OR²)₄]⁻, [M⁵(OR²)₅]⁻, [M⁶(OR²)₆]⁻, or[L_(n)NiX¹X²X³]⁻ where

L is a neutral mono- or polydentate Lewis base ligand

M⁴ is B, Al, Ga, or Y,

M⁵ is Ti, Zr, or Hf,

M⁶ is Nb or Ta,

n is the number of neutral ligands, L, that are coordinated to the Nicenter, and

each R² is independently hydrocarbyl, substituted hydrocarbyl, orsubstituted or unsubstituted hydrocarbyl silyl,

X¹, X², and X³ are independently an anionic organic or inorganic ligand.In one such embodiment, X¹, X², and X³ are independently halide,alkoxide, diketonate, amide and any two L or X ligands can be joinedtethered via a bridging moiety to form chelating ligands.

The nickel component of the liquid mixture may be derived from a rangeof soluble or dispersible nickel-containing source (starting) materialsthat chemically or thermally decompose to provide a source of nickel.For example, the source of nickel for the liquid mixture may comprise anickel derivative of an organic compound (e.g., an organo-nickelcompound) or a nickel salt of an organic or inorganic anion such asacetate, dienoate, hydroxide, carbonate, hydroxycarbonate, nitrate,sulfate, or hybrids comprising both organic and inorganic ligands. Incertain embodiments, nickel acetate is sometimes preferred.

A wide variety of organo-nickel compounds are described in theliterature and are useful as nickel sources for the liquid mixtures ofthis disclosure. In a preferred embodiment, the source material isdissolved in the liquid mixture to form a homogeneous solution that isfilterable through a 0.2 micron filter. For example, in one embodimentthe nickel source is a zero valent organo-nickel compound. Suitable zerovalent organo-nickel compounds include bis(cyclooctadiene)Ni.

More commonly, organo-nickel compounds where the nickel center is in aformal oxidation state of 2+ (Ni(II)) are used as sources of nickel inthe liquid mixtures of this disclosure. Exemplary Ni(II) complexesfurther include organic-ligand stabilized Ni(II) complexes correspondingto the formula L_(n)NiX⁴X⁵ wherein L is a neutral Lewis base ligand, nis the number of neutral Lewis ligands coordinated to the Ni center, andX⁴ and X⁵ are independently an organic or inorganic anionic ligand. Forexample, in one such embodiment, the nickel source corresponds to theformula L_(n)NiX⁴X⁵ wherein each L is independently a Lewis base ligandsuch as amine, pyridine, water, THF or phosphine and X⁴ and X⁵ areindependently a hydride, alkyl, alkoxide, allyl, diketonate, amide orcarboxylate ligand and any two L or X ligands can be joined via abridging moiety to form a chelating ligand. Exemplary Ni(II) complexesinclude Ni(II) complexes such as bis(cyclopentadienyl)Ni(II) complexes,Ni(II) allyl complexes including mixed cyclopentadienylNi(II)allylcomplexes, bis(aryl)Ni(II) complexes such as bis(mesityl)Ni(II),bis(acetate)Ni(II), bis(2-ethylhexanoate)Ni(II),bis(2,4-pentanedionato)Ni(II), and neutral Lewis base adducts thereof.

In one embodiment, the source (starting) material for the nickelcomponent of the liquid mixture comprises hydrolysable nickelcompositions. Hydrolysable nickel precursors are readily soluble in avariety of solvents including common organic solvents and react withatmospheric or intentionally added water to form Ni(OH)₂, and liberatethe anionic ligand in its protonated form (e.g., X—H) The ligand impartssolubility in organic solvents such as aliphatic and aromatichydrocarbons, ethers, and alcohols and generally affects the reactivityof the nickel complex. A key functional characteristic of thehydrolysable nickel precursor is to convert into a nickel hydroxide oroxide when exposed to water at low temperature (e.g., below 150° C.).Preferred hydrolysable nickel precursors are prepared using Ni-complexesthat are stabilized by substituted alkoxide ligands derived fromalcohols of the following general formulae:HOC(R³)(R⁴)C(R⁵)(R⁶)(R⁷)wherein R³, R⁴, R⁵, R⁶, and R⁷ are independently substituted orunsubstituted hydrocarbyl groups, at least one of R³, R⁴, R⁵, R⁶, and R⁷comprises an electronegative heteroatom, and where any of R³, R⁴, R⁵,R⁶, and R⁷ can be joined together to form a ring. The preferredelectronegative heteroatoms are oxygen or nitrogen. Preferred alkoxideligands [⁻OC(R³)(R⁴)C(R⁵)(R⁶)(R⁷)] are derived from alcohols in whichone or more R⁵, R⁶, and R⁷ is an ether or amine functional group. Anexemplary alkoxide ligand is the one derived from1-dimethylamino-2-propanol (DMAP): HOCH(Me)CH₂NMe₂. By way of furtherexample, in one embodiment the nickel composition is a hydrolysablenickel composition corresponding to the formula:

In one embodiment, the source (starting) material(s) for the bleachedstate stabilizing element(s) of the liquid mixture comprises a bleachedstate stabilizing element-containing composition that is soluble ordispersible in the liquid mixture and that chemically or thermallydecomposes to provide a source of the bleached state stabilizingelement(s) for the lithium nickel oxide film that is filterable througha 0.2 micron filter prior to the coating step. For example, in oneembodiment the bleached state stabilizing element source is anorganic-ligand stabilized metal complex or an organic or inorganic salt.For example, the salt may be a halide, nitrate, hydroxide, carbonate, orsulfate salt or an adduct thereof (e.g., acid, ether, amine or wateradducts) including combinations. For example the salts of organic acidsmay include acetic, lactic, citric, or oxalic.

In one embodiment, the source (starting) material for the bleached statestabilizing element(s) of the liquid mixture comprises hydrolysablebleached state stabilizing element compositions. Hydrolysable bleachedstate stabilizing element precursors are readily soluble in a variety ofsolvents including common organic solvents and react with atmospheric orintentionally added water to form bleached state stabilizing elementhydroxides and/or oxyhydroxides and/or oxides depending on the exactelement, and liberate the anionic ligand in its protonated form (e.g.,X—H). The ligand imparts solubility in organic solvents such asaliphatic and aromatic hydrocarbons, ethers, and alcohols and generallyaffects the reactivity of the complex. A key functional characteristicof the hydrolysable bleached state stabilizing element precursor is toconvert into a bleached state stabilizing element hydroxide or oxidewhen exposed to water at low temperature (e.g., below 150° C.).Preferred hydrolysable bleached state stabilizing element precursors areprepared using bleached state stabilizing element-complexes that arestabilized by substituted alkoxide ligands derived from alcohols of thefollowing general formulae:HOC(R³)(R⁴)C(R⁵)(R⁶)(R⁷)wherein R³, R⁴, R⁵, R⁶, and R⁷ are independently substituted orunsubstituted hydrocarbyl groups, at least one of R³, R⁴, R⁵, R⁶, and R⁷comprises an electronegative heteroatom, and where any of R³, R⁴, R⁵,R⁶, and R⁷ can be joined together to form a ring. The preferredelectronegative heteroatoms are oxygen or nitrogen. Preferred alkoxideligands [⁻OC(R³)(R⁴)C(R⁵)(R⁶)(R⁷)] are derived from alcohols in whichone or more R⁵, R⁶, and R⁷ is an ether or amine functional group. Anexemplary alkoxide ligand is the one derived from1-dimethylamino-2-propanol (DMAP): HOCH(Me)CH₂NMe₂.

As previously noted, any of the aforementioned bleached statestabilizing element source materials may also contain nickel and/orlithium in addition to the bleached state stabilizing element(s).

In one embodiment, the bleached state stabilizing element(s) is/areselected from the group consisting of organic derivatives of Y, Ti, Zr,Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, Sb and combinationsthereof. As previously mentioned, a wide variety of organic-ligandstabilized derivatives of these elements are known in the literature anduseful as components of the liquid mixtures of this disclosure. Theseinclude, preferably, complexes where the stabilizing organic ligands arealkoxides, carboxylates, diketonates, and amides. For metals havinghigher oxidations states such as the Group VI metals, oxo-derivativescomprising anionic organic ligands such as alkoxides are possibleincluding the (RO)₄MO, and (RO)₂MO₂ where M is Mo or W, O is oxygen, andR is a hydrocarbyl, substituted hydrocarbyl, or hydrocarbyl orsubstituted hydrocarbyl silyl group. By way of further example, in onesuch embodiment, the liquid mixture comprises at least one bleachedstate stabilizing element(s) selected from the group consisting of Y,Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, Sb andcombinations thereof. By way of further example, when the liquid mixturecomprises tungsten, tungsten (oxo) tetra(isopropoxide) and ammoniummetatungstate can be used with ammonium metatungstate being preferred incertain embodiments. When the liquid mixture comprises titanium,ammonium titanium lactate is preferred in certain embodiments. When theliquid mixture comprises zirconium, zirconyl nitrate and zirconiumacetate hydroxide may be used in certain embodiments with zirconylnitrate being sometimes preferred. When the liquid mixture comprisesniobium, ammonium niobate oxalate or niobium peroxo complexes may beused with peroxo complexes being sometimes preferred.

The solvent system may comprise a single solvent or a mixture ofsolvents in which source materials of the lithium, nickel and bleachedstate stabilizing element(s) are dissolved or dispersed. In oneembodiment, the solvent system comprises a protic organic solvent suchas alcohols, carboxylic acids and mixtures thereof. Exemplary proticorganic solvents include methanol, ethanol, 2,2,2-trifluouroethanol,1-propanol, 2-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol,and 2-ethoxyethanol; stearic acid, oleic acid, oleamine, andoctadecylamine and the like, and mixtures thereof. In anotherembodiment, the solvent system comprises a polar or nonpolar aproticsolvent. For example, in one such embodiment the solvent system maycomprise an alkane, and olefin, an aromatic, an ester or an ethersolvent or a combination thereof. Exemplary non-polar aprotic solventsinclude hexane, octane, 1-octadecene, benzene, toluene, xylene, and thelike. Exemplary polar aprotic solvents include, for example,N,N-dimethylformamide; 1,3-dimethyl-2-imidazolidinone;N-methyl-2-pyrrolidinone; acetonitrile; dimethylsulfoxide; acetone;ethyl acetate; benzyl ether, trioctylphosphine, and trioctylphosphineoxide, and the like, and mixtures thereof. Exemplary ethereal solventsinclude, for example, diethyl ether, 1,2-dimethoxyethane,methyl-tert-butyl ether, tetrahydrofuran, 1,4-dioxane, and the like, andmixtures thereof.

The liquid mixture may be formed by introducing the lithium, nickel andbleached state stabilizing element source materials into the solventsystem at a temperature typically in the range of about 15° C. to 350°C. Depending upon their chemical composition and stability, the lithium,nickel and bleached state stabilizing element source materials may bedissolved or dispersed in the solvent system under an inert atmosphere.In certain other embodiments, however, the lithium, nickel and bleachedstate stabilizing element source materials may be dissolved or dispersedin the solvent system in air or a synthetic air (N₂/O₂) ambient.Independent of ambient, the sequence in which the lithium, nickel andbleached state stabilizing element source material(s) are introduced tothe solvent system to form the liquid mixture may be varied to optimizeperformance. Thus, for example, in certain embodiments they may becombined with each other, or the solvent system in any sequence. By wayof further example, in one embodiment, the lithium, nickel and bleachedstate stabilizing element source materials for the liquid mixture arethree separate, chemically distinct materials. In another embodiment, atleast one of the source (starting) materials constitutes a source of acombination of at least two of lithium, nickel, and bleached statestabilizing element(s), e.g., (i) lithium and nickel, (ii) lithium andbleached state stabilizing element(s), (iii) nickel and bleached statestabilizing element(s), (iv) at least two bleached state stabilizingelements or (v) lithium, nickel and at least one bleached statestabilizing element.

The solvent system and/or the lithium, nickel and bleached statestabilizing element source materials for the liquid mixture may alsocontain a range of additives. For example, the liquid mixture maycontain solubility enhancers and complexing agents that stabilize theliquid mixture thermally and hydrolytically, such as organic acids,organic carbonates, and amines and polyethers. Particularly in regard tohydrolysis, the addition to and partial substitution of alkoxides bynucleophilic reagents comprising glycols, organic acids and diketonatesis known to reduce the degree and rates of hydrolysis. When working inmulti-metal liquid mixtures where varying rates of hydrolysis would beproblematic to compositional uniformity, the judicious adjustment ofboth the degree and the rates of hydrolysis is known to be important.Furthermore, since the degree and rates of hydrolysis are known to beimportant and adjustable, in certain embodiments, it is sometimespreferred to initiate partial hydrolysis intentionally through theaddition of water and/or acidic or basic catalysts to enhance thehydrolytic reactions. In one embodiment, an optimization of hydrolyticcontrol reagents is coupled with pre-hydrolysis through the intentionaladdition of water. In another embodiment, the addition of hydrolyticcontrol reagents is optimized for each component of the liquid mixture,individually. In another embodiment, pre-hydrolysis is optimized foreach component of the liquid mixture individually. In a furtherembodiment, an optimization of hydrolytic control reagents andpre-hydrolysis is performed for each component of the liquid mixture,individually. As noted above, in certain embodiments, the sourcematerials may be combined with each other or the solvent system in anysequence. In such embodiments, those of skill in the art shouldappreciate that the optimization of hydrolytic control reagents could beimpacted by both the sequence of additions and/or the exact solventsystems. Likewise, pre-hydrolysis could also be impacted by both thesequence of additions and/or exact solvent systems. Thus it should beunderstood that regardless of the sequence of additions or exact solventsystem that the hydrolytic control reagents and/or pre-hydrolysis are tobe optimized. The liquid mixture may also contain wetting agents such aspropylene glycol for enhancing the quality of the layers derived fromthe liquid mixture. In general, simple variation of lithium, nickel, andbleached state stabilizing element components in a solvent system willproduce homogeneous solutions that can be filtered through a 0.2 micronfilter without substantial loss of mass or change in the lithium,nickel, and bleached state stabilizing element composition.

In some embodiments, the formation of stable solutions of lithium,nickel and bleached state stabilizing element(s) may be aided by the useof acids and/or other complexing agents to minimize or even avoidprecipitation when the various lithium, nickel and bleached statestabilizing element precursors are combined. The addition of theseadditives may sometimes also be viewed as stabilizing in regard tohydrolysis, as noted previously. Common inorganic acids such ashydrochloric, sulfuric and nitric acid and organic acids such as acetic,propionic, ethoxyacetic, lactic, 2-(2-methoxyethoxy)acetic, acrylic,citric, 2-ethylhexanoic and glyoxylic acid may be used for this purpose.Preferred acids include organic acids such as ethoxyacetic and2-(2-methoxyethoxy)acetic acid. One of skill in the art will appreciatethat certain organic acids will both lower the pH of the liquid mixtureand minimize precipitation and that simple variation of the choice andconcentration of organic acid will sometimes lead to acceptable (stable,precipitate-free solutions) and will sometimes lead to non-acceptable(substantial precipitation) liquid mixtures. For example, when glyoxylicacid is used to lower the pH of the solution, a precipitate is oftenformed upon combination with one or more of the liquid mixtureprecursors. In some cases the pH is adjusted to promote the dissolutionof all the metal precursors in the mixture by the addition of base suchas ammonium hydroxide. The pH is preferably not adjusted above the pH atwhich any of the components precipitate from the solution.

In some embodiments, the addition of wetting agent additives is oftenpreferred for improving the film quality of the lithium mixed-metalnickel oxide material. Classes of additives include polymers such aspolyethers or polyols (e.g., polyethylene glycol), alcohols such asethanol or butanol, esters such as ethyl acetate, amino alcohols such asN,N-diethylamino ethanol, mixed alcohol ethers such as 2-ethoxyethanol,glycols such as propylene glycol with propylene glycol propyl ether andpropylene glycol monomethyl ether acetate sometimes being selected.

A polar organic solvent such as an alcohol, an ether solvent system, ora non-polar organic solvent such as toluene, hexane may be used. When apolar solvent is used, the use of organometallic complexes of lithium,nickel and other metal precursors is generally preferred. Exemplarylithium, nickel and other metal precursors include hydrolysablecomplexes such as alkoxides, aminoalkoxides, diolates, or amides thatreadily react to water, converting to hydroxides. Exemplary lithium andnickel precursors include their (N,N-dimethylamino-isopropoxide)complexes. Exemplary Group 4, Group 5, Group 6 and other bleached stateelement precursors include alkoxides, such as ethoxides, isopropoxides,butoxides, oxyalkoxides, or chloroalkoxides that are compatibly solublewith lithium and nickel precursors preferably with no precipitation. Oneexemplary method for forming liquid mixtures in a polar organic solvent,such as an alcohol solvent, comprises combining alkoxide complexes oflithium, bleached state metal(s), and nickel between 15° C. and 80° C.in an inert atmosphere.

When hydrolysable metal precursors are used, the coating solutions arereadily reactive to moisture in air or to intentionally added water,resulting in precipitation of their metal hydroxides, oxide orcarbonates. Therefore, addition of polar organic solvents that canmoderate hydrolysis is sometimes a preferred method for stabilizingthese solutions. Classes of additives include chelating alcohols oramino alcohols such as 2-methoxyethanols, dimethylaminoethanol, orpropyl amino ethanols, glycols such as propylene glycol, or ethyleneglycol, low-pKa solvents such as hexafluoropropanol with propyleneglycol or propylene carbonate are sometimes preferred.

In general, in those embodiments in which the liquid mixture compriseshydrolysable metal precursors (e.g., hydrolysable lithium sourcematerials, hydrolysable nickel source materials, or hydrolysablebleached state stabilizing elements, or a combination thereof), theliquid mixture coating solutions are readily reactive to moisture in airor to intentionally added water. Thus, a dispersed phase containinglithium, nickel, and/or bleached state stabilizing element) may beformed by introducing water to the liquid mixture. The introduction maybe achieved by adding water to the liquid mixture or generating water,in situ, in the liquid mixture by the addition of an agent thatliberates water. For example, acid or base catalysts have an impact.Specifically, acids can protonate alkoxide groups producing good leavinggroups and generating water as shown in the reaction below:M—OR+H₃O⁺→M⁺←:OHR+H₂O  (5)Such a reaction can also impact the resulting morphology of the colloidproduct. As a further example, in one embodiment, at least about 0.05equivalents of water are introduced (e.g., added or generated in situ)to the liquid mixture per equivalent of hydrolysable metal. By way offurther example, in one embodiment at least about 0.1 equivalents ofwater are introduced to the liquid mixture per equivalent ofhydrolysable metal. By way of further example, in one embodiment atleast about 0.2 equivalents of water are introduced to the liquidmixture per equivalent of hydrolysable metal. By way of further example,in one embodiment at least about 0.3 equivalents of water are introducedto the liquid mixture per equivalent of hydrolysable metal. By way offurther example, in one embodiment at least about 0.4 equivalents ofwater are introduced to the liquid mixture per equivalent ofhydrolysable metal. By way of further example, in one embodiment atleast about 0.5 equivalents of water are introduced to the liquidmixture per equivalent of hydrolysable metal. By way of further example,in one embodiment at least about 0.6 equivalents of water are introducedto the liquid mixture per equivalent of hydrolysable metal. By way offurther example, in one embodiment at least about 0.7 equivalents ofwater are introduced to the liquid mixture per equivalent ofhydrolysable metal. By way of further example, in one embodiment atleast about 0.8 equivalents of water are introduced to the liquidmixture per equivalent of hydrolysable metal. By way of further example,in one embodiment at least about 0.9 equivalents of water are introducedto the liquid mixture per equivalent of hydrolysable metal. By way offurther example, in one embodiment at least about 1 equivalent of wateris introduced to the liquid mixture per equivalent of hydrolysablemetal. In general, however, in such embodiments less than about 3equivalents of water will typically be introduced to the liquid mixtureper equivalent of hydrolysable metal. For example, in one suchembodiment no more than at least about 2.5 equivalents of water areintroduced to the liquid mixture per equivalent of hydrolysable metal.By way of further example, in one embodiment no more than about 2.25equivalents of water are introduced to the liquid mixture per equivalentof hydrolysable metal. By way of further example, in one embodiment nomore than about 2 equivalents of water are introduced to the liquidmixture per equivalent of hydrolysable metal. By way of further example,in one embodiment no more than about 1.75 equivalents of water areintroduced to the liquid mixture per equivalent of hydrolysable metal.By way of further example, in one embodiment no more than about 1.5equivalents of water are introduced to the liquid mixture per equivalentof hydrolysable metal. Exemplary ranges of water introduced to theliquid mixture per equivalent of hydrolysable metal thus include0.1-2.25, 0.25-2, and 0.5-1.5 equivalents of water per equivalent ofhydrolysable metal. As noted, instead of adding (exogenous) water to thesystem, water may be introduced by in situ generation of water. It isunderstood by one of skill in the art that the ranges described abovecomprise the sum of exogenous and in situ generated water.

Furthermore, in those embodiments in which the liquid mixture compriseshydrolysable metal precursors (e.g., hydrolysable lithium sourcematerials, hydrolysable nickel source materials, or hydrolysablebleached state stabilizing elements, or a combination thereof), the useof hydrolytic control agents, as described above, for example chelatingagents, may be important to control the rate and degree of hydrolysis,particularly if a goal of controlled partial hydrolysis is to berealized. Thus, if a dispersed phase containing lithium, nickel, and/orbleached state stabilizing element is to be formed by introducing waterto the liquid mixture, the coordination sphere of the hydrolysable metalprecursors may be adapted through the use of chelating agents such asnucleophilic reagents comprising glycols, organic acids and diketonates.If the chelating agents are overused however hydrolysis rates may be soattenuated as to prevent the desired degree of partial hydrolysis. Forexample, in one embodiment, at least about 0.05 equivalents ofcomplexing agent are introduced to the liquid mixture per equivalent ofhydrolysable metal. By way of further example, in one embodiment atleast about 0.1 equivalents of complexing agent are introduced to theliquid mixture per equivalent of hydrolysable metal. By way of furtherexample, in one embodiment at least about 0.2 equivalents of complexingagent are introduced to the liquid mixture per equivalent ofhydrolysable metal. By way of further example, in one embodiment atleast about 0.3 equivalents of complexing agent are introduced to theliquid mixture per equivalent of hydrolysable metal. By way of furtherexample, in one embodiment at least about 0.4 equivalents of complexingagent are introduced to the liquid mixture per equivalent ofhydrolysable metal. By way of further example, in one embodiment atleast about 0.5 equivalents of complexing agent are introduced to theliquid mixture per equivalent of hydrolysable metal. By way of furtherexample, in one embodiment at least about 0.6 equivalents of complexingagent are introduced to the liquid mixture per equivalent ofhydrolysable metal. By way of further example, in one embodiment atleast about 0.7 equivalents of complexing agent are introduced to theliquid mixture per equivalent of hydrolysable metal. By way of furtherexample, in one embodiment at least about 0.8 equivalents of complexingagent are introduced to the liquid mixture per equivalent ofhydrolysable metal. By way of further example, in one embodiment atleast about 0.9 equivalents of complexing agent are introduced to theliquid mixture per equivalent of hydrolysable metal. By way of furtherexample, in one embodiment at least about 1 equivalent of complexingagent is introduced to the liquid per equivalent of hydrolysable metal.By way of further example, in one embodiment at least about 1.25equivalents of complexing agent is introduced to the liquid perequivalent of hydrolysable metal. By way of further example, in oneembodiment at least about 1.5 equivalents of complexing agent isintroduced to the liquid per equivalent of hydrolysable metal. Ingeneral, however, in such embodiments less than about 3 equivalents ofcomplexing agent will typically be introduced to the liquid mixture perequivalent of hydrolysable metal. For example, in one such embodiment nomore than at least about 2.75 equivalents of complexing agent areintroduced to the liquid mixture per equivalent of hydrolysable metal.For example, in one such embodiment no more than at least about 2.5equivalents of complexing agent are introduced to the liquid mixture perequivalent of hydrolysable metal. By way of further example, in oneembodiment no more than about 2.25 equivalents of complexing agent areintroduced to the liquid mixture per equivalent of hydrolysable metal.By way of further example, in one embodiment no more than about 2equivalents of complexing agent are introduced to the liquid mixture perequivalent of hydrolysable metal. By way of further example, in oneembodiment no more than about 1.75 equivalents of complexing agent areintroduced to the liquid mixture per equivalent of hydrolysable metal.Exemplary ranges of complexing agent introduced to the liquid mixtureper equivalent of hydrolysable metal thus include 0.25-2.75, 0.5-2.5,and 0.75-2.25 equivalents of complexing agent per equivalent ofhydrolysable metal. In each of the embodiments recited in thisparagraph, the complexing agent may be, for example, a coordinating acidsuch as ethoxyacetic acid.

Anodic Electrochromic Layer Preparation

In accordance with one aspect of the present disclosure, anodicelectrochromic layers may be prepared from the liquid mixtures in aseries of steps. In general, a film is formed from the liquid mixture ona substrate, solvent is evaporated from the liquid mixture, and the filmis treated to form the anodic electrochromic layer. In one suchembodiment, the film is thermally treated to form the anodicelectrochromic layer.

In one embodiment, the process comprises a solution-based synthesis ofelectrochromic lithiated nickel oxide thin films where theorganometallic metal precursors in an organic solvent are partiallyhydrolyzed with water in the presence of acid prior to deposition onto asubstrate. Reproducible electrochemical performance is thus enabled byimproving the stability of the coating solutions against moisture andCO₂. This disclosure also provides substantial reduction in cracking ofthe calcined films

In one exemplary embodiment, a method of the present disclosure involvespreparing a metal precursor solution that includes hydrolysableorganometallic Li and Ni complexes and/or a stabilizing metal dopant inan organic solvent, modifying those complexes with an appropriate amountof an organic acid and partially hydrolyzing the solution through theaddition of controlled amounts of water. The rate and the degree ofhydrolysis of these multi metal-precursors are controlled by adjustingthe equivalencies of water and acid relative to their alkoxide ligands.The resulting solutions are suitable for coating by a variety of methodssuch as spin coating, slot-die coating, or spray coating. Thepre-hydrolyzed formulations don't require complex post-coating humiditytreatments, thus reducing processing time and energy.

Advantageously, pre-hydrolyzed solutions are less reactive to thecoating and drying environment, which is ambient air. The coordinationof chelating organic acids to the metals efficiently protects the systemfrom reaction with water and/or carbon dioxide such that the compositionof the wet-deposition is maintained without converting to carbonatesduring the drying procedure. Thus the coating quality and the ECperformance of the calcined materials are demonstrably morereproducible.

Another advantage of a synthesis method in accordance with oneembodiment of the present disclosure is that it can provide homogeneousand stable solutions containing multiple metals that inherently havedifferent rates and degrees of hydrolysis that can cause precipitationupon mixing. Especially, this disclosure provides various ways ofcontrolled pre-hydrolysis for primary-, binary, or ternary-metalsolutions to afford homogenous and stable coating solutions forhigh-performing lithium nickel metal oxide electrochromic materials.

Also, the pre-hydrolysis process replaces alkoxides withhydroxides/oxides liberating free alcohols prior to coating. Therefore,the process avoids a significant mass change on the substrate duringcoating, drying and calcination steps, which produces substantially lesscracked films without requiring the addition of anti-cracking additives.

In one embodiment, the liquid mixture may be deposited onto anysubstrate having suitable optical, electrical, thermal, and mechanicalproperties. Such substrates include, for example, glass, plastic, metal,and metal coated glass or plastic. Non-exclusive examples of possibleplastic substrates are polycarbonates, polyacrylics, polyurethanes,urethane carbonate copolymers, polysulfones, polyimides, polyacrylates,polyethers, polyester, polyethylenes, polyalkenes, polyimides,polysulfides, polyvinylacetates and cellulose-based polymers. If aplastic substrate is used, it may be barrier protected and abrasionprotected using a hard coat of, for example, a diamond-like protectivecoating, a silica/silicone anti-abrasion coating, or the like, such asis well known in the plastic glazing art. Suitable glasses includeeither clear or tinted soda lime glass, chemically tempered soda limeglass, heat strengthened soda lime glass, tempered glass, orborosilicate glass.

In one embodiment, the substrate comprises a transparent conductivelayer (as described in connection with FIG. 1) on glass, plastic, metal,and metal coated glass or plastic. In this embodiment, the liquidmixture may be deposited directly onto the surface of the transparentconductive layer. In one embodiment, the transparent conductive layer isa transparent conductive oxide layer such as fluorinated tin oxide(“FTO”).

In another embodiment, the substrate comprises a current modulatinglayer (as described in connection with FIG. 2) on glass, plastic, metal,and metal coated glass or plastic. In this embodiment, the liquidmixture may be deposited directly onto the surface of the currentmodulating layer.

In another embodiment, the substrate comprises an ion conductor layer(as described in connection with FIG. 1) on glass, plastic, metal, andmetal coated glass or plastic. In this embodiment, the liquid mixturemay be deposited directly onto the surface of the ion conductor layer.

A range of techniques may be used to form a layer that is derived fromthe liquid mixture on the substrate. In one exemplary embodiment, acontinuous liquid layer of the liquid mixture is applied to thesubstrate by meniscus coating, roll coating, dip coating, spin coating,screen printing, spray coating, ink jet coating, knife over roll coating(gap coating), metering rod coating, curtain coating, air knife coating,and partial immersion coating and like, and solvent is then removed.Alternatively, the layer may be formed by directing droplets of theliquid mixture toward the substrate by spray or ink jet coating, andremoving solvent. Regardless of technique, a layer is formed on thesubstrate containing lithium, nickel and at least one bleached statestabilizing element in the ratios previously described herein inconnection with the electrochromic anodic layers. That is, the relativeamounts of lithium, nickel and the bleached state stabilizing elementsin the layer are controlled such that an atomic ratio of lithium to thecombined amount of nickel and bleached state stabilizing element(s) andthe atomic ratio of the combined amount of all bleached statestabilizing element(s) to nickel is as previously described inconnection with the liquid mixture.

In those embodiments in which the lithium composition, nickelcomposition and/or bleached state stabilizing element composition(s) arehydrolysable, it may be desirable to form the layer on the substrate ina controlled atmosphere. For example, in one embodiment, deposition ofthe liquid mixture occurs in an atmosphere having a relative humidity(RH) of less than 55% RH. By way of further example, in one suchembodiment, deposition of the liquid mixture occurs in an atmospherehaving a relative humidity not in excess of 40% RH. By way of furtherexample, in one such embodiment, deposition of the liquid mixture occursin an atmosphere having a relative humidity not in excess of 30% RH. Byway of further example, in one such embodiment, deposition of the liquidmixture occurs in an atmosphere having a relative humidity not in excessof 20% RH. By way of further example, in one such embodiment, depositionof the liquid mixture occurs in an atmosphere having a relative humiditynot in excess of 10% RH or even not in excess of 5% RH. In someembodiments, the atmosphere may be even drier; for example, in someembodiments, deposition may occur in a dry atmosphere defined by a RH ofless than 5% RH, less than 1% RH, or even less than 10 ppm water. Insome embodiments, however, the control of relative humidity may be lessimportant if appropriate amounts of water are added in an appropriatemanner directly to the liquid mixture, for example if added to inducepartial hydrolysis.

The deposition of the liquid mixture onto the substrate may be carriedout in a range of atmospheres. In one embodiment, the liquid mixture isdeposited in an inert atmosphere (e.g., nitrogen or argon) atmosphere.In an alternative embodiment, the liquid mixture is deposited in anoxygen-containing atmosphere such as compressed dry air or synthetic air(consisting of a mixture of oxygen and nitrogen in approximately 20:80v/v ratio). In certain embodiments, for example, when the liquid mixturecomprises a hydrolysable precursor for the lithium, nickel, and/orbleached state stabilizing element(s), performance may be improved byminimizing the liquid mixture's and the deposited film's exposure toCO₂; For example, in some embodiments the ambient may have a CO₂concentration of less than 50 ppm, less than 5 ppm or even less than 1ppm. In some embodiments, however, the control of an oxygen-containingatmosphere and/or the control of CO₂ concentration may be less importantto performance.

The temperature at which the liquid mixture is deposited onto thesubstrate may range from near room temperature to elevated temperatures.For spray coating, for example, the maximum high temperature would belimited by the substrate stability (e.g., 550 to 700° C. for glass, lessthan 250° C. for most plastics, etc.) and the desired annealingtemperature for the layer. For coating techniques in which a continuousliquid film is applied to a substrate, for example, coating temperatureswill typically be in range of room temperature 25° C. to about 80° C.

After the substrate is coated with the liquid mixture, the resultingfilms may be placed under an air stream, vacuum, or heated to achievefurther drying in order to remove residual solvent. The composition ofthe ambient atmosphere for this step may be controlled as previouslydescribed in connection with the coating step. For example, theatmosphere may have a relative humidity of less than 1% to 55% RH, itmay be an inert atmosphere (nitrogen or argon), or it may containoxygen.

In those embodiments in which the liquid mixture contains a hydrolysableprecursor for the lithium, nickel, or bleached state stabilizingelement, the coated substrate may then be exposed to a humid atmosphere(e.g., a RH of at least 30% RH) to hydrolyze the metal complex(es) toform a protonated ligand bi-product and a lithium nickel hydroxide film.Such exposure may be carried out, for example, at a temperature in therange about 40° C. to about 200° C. for a period of about 5 minutes toabout 4 hours. In some embodiments, a second thermal processing step attemperatures above 200° C., preferably above 250° C., to form an oxidefilm having substantially lower levels of hydroxide content. In someembodiments, however, exposure of the coated substrate to a humidatmosphere may be less important if appropriate amounts of water areadded in an appropriate manner directly to the liquid mixture.

In one embodiment, the coated substrate is heat-treated (annealed) toform the anodic electrochromic layer. Depending upon the composition ofthe liquid mixture and the substrate stability, the coated substrate isannealed at a temperature of at least about 200° C. For example, in oneembodiment the substrate may be annealed at a temperature at the lowerend of this range, e.g., at least about 250° C. but less than about 700°C.; temperatures within this range would be particularly advantageousfor polymeric substrates that may lose dimensional stability at greatertemperatures. In other embodiments, the coated substrate may be annealedat a temperature in the range about 300° C. to about 650° C. By way offurther example, in one such embodiment the coated substrate may beannealed at a temperature in the range of about 350° C. to about 500° C.In general, however, annealing temperatures will typically not exceedabout 750° C. The anneal time may range from several minutes (e.g.,about 5 minutes) to several hours. Typically, the anneal time will rangefrom about 30 minutes to about 2 hours. Additionally, the annealingtemperature may be achieved (i.e., the ramp rate from room temperatureto the annealing temperature) over a period ranging from 1 minute toabout several hours.

In some embodiments it may be desirable to heat-treat the coatedsubstrate in a controlled atmosphere. For example, in one embodiment,the coated substrate is annealed in an atmosphere having a relativehumidity (RH) of about 5% to 55% RH. By way of further example, in onesuch embodiment, the coated substrate is annealed in an atmospherehaving a relative humidity not in excess of 10% RH or even not in excessof 5% RH. In some embodiments, the atmosphere may be even drier; forexample, in some embodiments, the coated substrate is annealed in a dryatmosphere defined by a RH of less than 5% RH, less than 1% RH, or evenless than 10 ppm water. In some embodiments, however, the control of theannealing atmosphere in terms of relative humidity may be lessimportant.

In some embodiments, the composition of the carrier gas in which theheat-treatment is carried out may be an inert (e.g., nitrogen or argon)atmosphere. Alternatively, it may contain oxygen (e.g., compressed dryair or synthetic air consisting of a mixture of oxygen and nitrogen inapproximately 20:80 v/v ratio) environment. In certain embodiments,performance may be improved by reducing the exposure to CO₂ usingatmospheres in which the CO₂ concentration is less than 50 ppm. Forexample, in some embodiments the CO₂ concentration may be less than 5ppm or even less than 1 ppm. In some embodiments, however, the controlof an oxygen-containing atmosphere and/or the control of CO₂concentration may be less important to performance.

The coated substrate may be heat-treated (annealed) by various means. Inone embodiment, the coated substrate is heat-treated (annealed) in arapid thermal annealer in which heating occurs primarily throughabsorption of radiative energy by the layer and/or the substrate. Inanother embodiment, the coated substrate is heat-treated (annealed) in abelt furnace in which heating occurs in one or more zones in acontinuous process. In another embodiment, the coated substrate isheat-treated (annealed) in a convection oven and furnaces in whichheating is achieved in a batch process by a combination of radiative andconductive processes. In another embodiment, the coated substrate isheat-treated (annealed) using a hot plate (bake plate) or surfaceheating where heating occurs primarily by conduction by placing thesubstrate on or slightly above a heated surface; examples includeproximity baking where the sample is held above a plate using a cushionof air, hard contact baking where the substrate is held to the surfaceof a heated surface via vacuum or some other method, and soft contactbaking where the substrate rests on a heated surface via gravity alone.

In some embodiments, the resulting anodic electrochromic layer has anaverage thickness between about 25 nm and about 2,000 nm. For example,in one such embodiment the anodic electrochromic layer has a thicknessof about 50 nm to about 2,000 nm. By way of further example, in one suchembodiment the anodic electrochromic layer has a thickness of about 25nm to about 1,000 nm. By way of further example, in one such embodiment,the anodic electrochromic layer has an average thickness between about100 nm and about 700 nm. In some embodiments, the anodic electrochromiclayer has a thickness of about 250 nm to about 500 nm.

Depending upon the method of deposition and the solvent system comprisedby the liquid mixture, the resulting electrochromic nickel oxide layermay comprise a significant amount of carbon. For example, in oneembodiment, the anodic electrochromic layer contains at least about 0.01wt % carbon. By way of further example, in one embodiment theelectrochromic nickel oxide material contains at least about 0.05 wt %carbon. By way of further example, in one embodiment the anodicelectrochromic material contains at least about 0.1 wt % carbon. By wayof further example, in one embodiment the anodic electrochromic materialcontains at least about 0.25 wt % carbon. By way of further example, inone embodiment the anodic electrochromic material contains at leastabout 0.5 wt % carbon. Typically, however, the anodic electrochromicmaterial will generally contain no more than about 5 wt % carbon. Thus,for example, in one embodiment, the anodic electrochromic material willcontain less than 4 wt % carbon. By way of further example, in oneembodiment the anodic electrochromic material will contain less than 3wt % carbon. By way of further example, in one embodiment the anodicelectrochromic material will contain less than 2 wt % carbon. By way offurther example, in one embodiment the anodic electrochromic materialwill contain less than 1 wt % carbon. Thus, in certain embodiments, theanodic electrochromic material may contain 0.01 wt % to 5 wt % carbon.By way of further example, in certain embodiments, the anodicelectrochromic material may contain 0.05 wt % to 2.5 wt % carbon. By wayof further example, in certain embodiments, the anodic electrochromicmaterial may contain 0.1 wt % to 2 wt % carbon. By way of furtherexample, in certain embodiments, the anodic electrochromic material maycontain 0.5 wt % to 1 wt % carbon.

EXAMPLES

The following non-limiting examples are provided to further illustratethe present disclosure. It should be appreciated by those of skill inthe art that the techniques disclosed in the examples that followrepresent approaches the inventors have found function well in thepractice of the disclosure, and thus can be considered to constituteexamples of modes for its practice. However, those of skill in the artshould, in light of the present disclosure, appreciate that many changescan be made in the specific embodiments that are disclosed and stillobtain a like or similar result without departing from the spirit andscope of the disclosure.

Example 1: Synthesis of Li₁Ni_(0.67)Nb_(0.33)O_(z) from a Pre-HydrolyzedSolution Prepared by Gelation with Water and then Re-Dissolution withAcid

Hydrolysable Ni(II) precursor compound (Ni(DMAP)₂,DMAP=1-dimethylamino-2-propanolate) was synthesized by a modification ofthe known method (Hubert-Pfalzgraf et. al. Polyhedron, 16 (1997)4197-4203). LiDMAP compound was synthesized by the reaction ofn-butyl-lithium and DMAPrOH (1-dimethylamino-2-propanol).

In EtOH (1.1 mL), were dissolved LiDMAP (0.32 g), Nb(OEt)₅ (0.30 g) andNi(DMAP)₂ (0.51 g) resulting in a 2.9 M solution (by total metal) underan N₂ atmosphere in the glove box. The solution then was taken out ofthe glove box, and to which was added dropwise a 10% water in ethanolsolution (v/v, 1.46 mL) using a syringe under vigorous stirring. Thesolution became green, and turned to a gel under mild heating. Then thetransparent green gel was digested by adding ethoxyacetic acid (0.496mL) at 60° C. After being cooled down the solution was filtered through0.2 μm filter, and was spun onto an FTO (fluorine-doped tin oxide)substrate at 1000 rpm for 20 sec under an N₂ atmosphere. Then the wetdeposition was dried under Ar, and was heated at 400° C. under CDA with40% relative humidity (RH) for an hour.

After cooling, the film was brought into an Ar-filled glove box, and theelectrochromic properties were examined in a combinedelectrochemical/optical setup consisting of a three-electrode cell in acuvette placed in the path of a white light source and spectrometer.Data were obtained by sequential oxidation and reduction undergalvanostatic control followed by a constant voltage hold (CC-CV). Theelectrolyte was 1 M LiClO₄ in propylene carbonate. Typically a voltagerange of 2.5-4.0 V vs Li/Li+ was applied. Separate pieces of lithiummetal were used as the reference and counter electrodes. Optical datawere recorded every 1-5 s. Coloration Efficiency (CE) was calculatedfrom the transmission data (at 550 nm) and the amount of charge passedduring the second reduction event over the applied voltage range.

Film thickness was measured by profilometry to be 246 nm, and themeasured charge capacity was 14.5 mC/cm₂ over the applied voltage range.The films switched from a bleached state transmission of 85.9% to a darkstate transmission of 21.2% (at 550 nm). Absolute CE was 26.4 cm²/C.

Example 2: Synthesis of Li_(1.0)Ni_(0.67)Nb_(0.33)O_(z) from aPre-Hydrolyzed Solution with a Mixture of Water and Acid

In 1-PnOH (1.301 g), were dissolved LiDMAP (0.474 g), Nb(OEt)₅ (0.472 g)and Ni(DMAP)₂ (0.793 g) resulting in a 3.0 M solution (by total metal)under an N₂ atmosphere in the glove box. The solution then was taken outof the glove box, and to 1.0 mL of the solution was added dropwise awater/ethoxyacetic acid/1-PnOH 20%/25%/55% solution (v/v, 0.431 mL)using a syringe under vigorous stirring. The solution became green, andwas allowed to stir for 20 min at RT. Then the solution was filteredthrough 0.2 μm filter, and was spun onto an FTO substrate at 800 rpm for30 sec under an N₂ atmosphere. Then the wet deposition was dried underAr, and was heated at 400° C. under CDA (40% RH) for an hour.

After cooling, the film was brought into an Ar-filled glove box, and theelectrochromic properties were examined as described in Example 1.

Film thickness was measured by profilometry to be 263 nm, and themeasured charge capacity was 23 mC/cm² over the applied voltage range.The film switched from a bleached state transmission of 85% to a darkstate transmission of 21% (at 550 nm). Absolute coloration efficiencywas 27.4 cm²/C.

Examples 3-8: Synthesis of Li_(1.3)Ni_(0.67)M_(0.33)O_(z) (M=Ta, Ti, Zr,Hf, Sb, and V) from Pre-Hydrolyzed Solutions with a Mixture of Water andAcid

The coating solution of each material was prepared with the same methodas described in Example 2, by pre-hydrolyzing the Li, Ni and stabilizingmetal precursor solutions with water and ethoxyacetic acid by adding acertain amount of a water/ethoxyacetic acid/1-PnOH 20%/25%/55% solution.All the metal solutions afforded green solutions with small differencesin brightness. Metal precursor compounds of Ti(iOPr)₄, Zr(nOBu)₄,Hf(nOBu)₄, Sb(nOBu)₃, and V(0)(iOPr)₃ were used for producing Ti, Zr,Hf, Sb and V-doped LiNiOx, respectively. Coating, calcination, andelectrochemical analysis were performed with the same processingparameters shown in Example 1. Electrochemical results with filmthicknesses of the calcined films are listed in Table 2.

TABLE 2 Electrochromic data for the thin films ofLi_(1.3)Ni_(0.67)M_(0.33)O_(z) (M = Ta, Ti, Zr, Hf, Sb, and V). Abs. ofColoration Charge T_(bleached) T_(colored) at efficiency at Thicknesscapacity at 550 nm 550 nm 550 nm No Materials (nm) (mC/cm²) (%) (%)(cm²/C) 3 Li_(1.3)Ni_(0.67)Ta_(0.33)Oz 187-277 4-18 75-89 26-48 23-33 4Li_(1.3)Ni_(0.67)Ti_(0.33)Oz 5 Li_(1.3)Ni_(0.67)Hf_(0.33)Oz 6Li_(1.3)Ni_(0.67)Zr_(0.33)Oz 7 Li_(1.3)Ni_(0.67)Sb_(0.33)Oz 8Li_(1.3)Ni_(0.67)V_(0.33)Oz

Examples 9-13: Synthesis of Li_(1.0)Ni_(0.67)M_(0.33)O_(z) where M=Nbfrom Pre-Hydrolyzed Primary- or Ternary-Metal Solutions Prepared byVarious Mixing Orders of Water and Acid

For the use of primary metal solutions, individual metal solutions ofLiDMAP (2.0M), Ni(DMAP)₂ (2.0M), and Nb(OEt)₅ (2.0M) in ethanol wereprepared in an N₂ atmosphere in a glovebox. Then the solutions weretaken out of the box, and a 10% water mixture and ethoxyacetic acid wereadded in different orders to the solutions, maintaining a molar ratio ofwater to acid of 1 to 1, as described in the Table 3 below. The resultedsolutions were then mixed to the molar ratio of Li:Ni:Nb=1.0:0.67:0.33.

For the use of ternary metal solutions, a solution containing LiDMAP,Ni(DMAP)₂ and Nb(OEt)₅ with a 1:0.67:0.33 molar ratio in 1-PnOH wereprepared in an N₂ atmosphere in a glovebox. Then the solutions weretaken out of the box, and a 10% water mixture and ethoxyacetic acid wereadded in different orders to the solutions, as described in the Table 3below. Both cases afforded transparent green coating solutions.

The combined solutions from above were filtered through 0.2 μm filter,and were spun onto FTO substrates at 800 rpm for 30 sec under an N2atmosphere. Then the wet depositions were dried under Ar, and wereheated at 400° C. under CDA (40% RH) for an hour.

After cooling, the films were brought into an Ar-filled glove box, andthe electrochromic properties were examined as described in Example 1.Electrochemical results with film thicknesses of the calcined films arelisted in Table 3.

TABLE 3 Various mixing orders of water and acid to primary- orternary-metal precursor solutions for Li_(1.0)Ni_(0.67)M_(0.33)O_(z),where M = Nb, and the electrochromic data of the calcined films.T_(bleached) and Abs. of T_(colored) Coloration 1^(st) Charge atefficiency addition 2^(nd) addition capacity Thickness 550 nm at 550 nmNo Precursor solution reagent reagent (mC/cm²) (nm) (%) (cm²/C) 9 LiDMAPacid 10% water 10.7 168 87, 49 24.8 NiDMAP2 acid 10% water Nb(OEt)5 acid10% water 10 LiDMAP 10% water acid 11.6 182 86, 43 26.4 NiDMAP2 10%water acid Nb(OEt)5 10% water acid 11 LiDMAP acid Mixed them 17.2 10384, 18 37.1 NiDMAP2 acid all and Nb(OEt)5 acid added 10% water (excess)12 LiDMAP/NiDMAP2/ 10% water Acid 16.1 229 89, 32 27.0 Nb(OEt)5 13LiDMAP/NiDMAP2/ acid 10% water 16.4 219 89, 33 26.2 Nb(OEt)5

Example 14: Synthesis of Li₁Ni_(0.67)Nb_(0.33)O_(z) fromNon-Hydrolysable Li and Ni Precursor Compounds

To a dispersion of LiOH (0.23 g) in ethanol, was added ethoxyacetic acid(1.04 g) under stirring, affording a clear solution. In a separate vial,Ni(OAc)₂.4H₂O (1.24 g) and diethanolamine (1.29 g) were mixed in EtOHunder stirring, and the solution became blue upon complete dissolution.To a 3 M Nb(OEt)₅ in 1-pentanol in a separate vial, was dropwise addedethoxyacetic acid (1.25 mL) under stirring, and then was added a mixtureof water10%/ethanol18%/1-pentanol74% (0.9 mL). Then the Li, Ni, and Nbsolutions were mixed up with the molar ratio of Li:Ni:Nb=4:2:1, whichafforded a green solution. The solution was filtered through 0.2 μmfilter, and was spun onto an FTO (fluorine-doped tin oxide) substrate at1000 rpm for 20 sec under an N₂ atmosphere. Then the wet deposition wasdried under Ar, and was heated at 400° C. under CDA with 40% relativehumidity (RH) for an hour.

After cooling, the film was brought into an Ar-filled glove box, and theelectrochromic properties were examined in the manner of Example 1.

Film thickness was measured by profilometry to be 183 nm, and themeasured charge capacity was 8.9 mC/cm₂ over the applied voltage range.The film switched from a bleached state transmission of 89% to a darkstate transmission of 49% (at 550 nm). Absolute CE was 28 cm²/C.

What is claimed is:
 1. A process for preparing a multi-layerelectrochromic structure, the process comprising: depositing a film of aliquid mixture comprising lithium, nickel, and at least one bleachedstate stabilizing element onto a surface of a substrate, and treatingthe deposited film to form an anodic electrochromic layer comprising alithiated nickel oxide, wherein (i) the atomic ratio of lithium to thecombined amount of nickel and the bleached state stabilizing element inthe anodic electrochromic layer is at least 0.4:1, (ii) the atomic ratioof the amount of the bleached state stabilizing element to the combinedamount of nickel and the bleached state stabilizing elements in theanodic electrochromic layer is at least 0.025:1, (iii) the bleachedstate stabilizing element is selected from the group consisting of Y,Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, Sb andcombinations thereof, and (iv) the liquid mixture comprises a dispersedphase and a continuous phase, the dispersed phase comprising a dispersedspecies having a number average size of at least 5 nm.
 2. The process ofclaim 1 wherein the dispersed species has a number average size selectedfrom the group consisting of at least 10 nm, at least 25 nm, at least 50nm, at least 75 nm, and at least 100 nm.
 3. The process of claim 1wherein the dispersed species comprises discrete particles.
 4. Theprocess of claim 1 wherein the substrate comprises a transparentconductive layer and a glass, plastic, metal, or metal-coated glass orplastic layer, and the surface of the substrate onto which the liquidmixture is deposited is a surface of the transparent conductive layer.5. The process of claim 1 wherein the nickel component of the liquidmixture is derived from an organic-ligand stabilized Ni(II) complexcorresponding to the formula L_(n)NiX⁴X⁵ wherein L is a neutral Lewisbase ligand, n is the number of neutral Lewis ligands coordinated to theNi center, and X⁴ and X⁵ are independently an organic or inorganicanionic ligand.
 6. The process of claim 1 wherein the nickel componentof the liquid mixture is a hydrolysable nickel composition derived from(i) nickel or a nickel-containing composition and (ii) an alcohol havingthe formula:HOC(R³)(R⁴)C(R⁵)(R⁶)(R⁷) wherein R³, R⁴, R⁵, R⁶, and R⁷ areindependently substituted or unsubstituted hydrocarbyl groups, at leastone of R³, R⁴, R⁵, R⁶, and R⁷ comprises an electronegative heteroatom,and where any of R³, R⁴, R⁵, R⁶, and R⁷ can be joined together to form aring.
 7. The process claim 1 wherein the atomic ratio of lithium to thecombined amount of nickel and the bleached state stabilizing element inthe liquid mixture is at least 0.4:1, the atomic ratio of the combinedamount of the bleached state stabilizing element to the combined amountof nickel and the bleached state stabilizing elements in the liquidmixture is in the range of 0.025:1 to 0.8:1, and the bleached statestabilizing element in the liquid mixture is selected from the groupconsisting of Y, Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge,Sn, Sb and combinations thereof.
 8. The process of claim 1 wherein thedeposited material is thermally treated at an annealing temperature ofat least 200° C. and for an annealing time of two hours to form theanodic electrochromic layer.
 9. The process of claim 1 wherein theprocess further comprises combining a lithium source material, a nickelsource material and at least one bleached state stabilizing elementsource material in a solvent system, at least one of the lithium, nickeland bleached state stabilizing element source materials being ahydrolysable source material, and hydrolyzing the hydrolysable sourcematerial to form the liquid mixture.
 10. The process of claim 9 whereinthe hydrolysable lithium source material is a metal alkoxide comprisinglithium, nickel or the bleached state stabilizing element.
 11. Theprocess of claim 9 wherein the hydrolysable source material ishydrolyzed by adding water to the liquid mixture.
 12. The process ofclaim 9 wherein the hydrolysis rate and degree of hydrolysis of thehydrolysable source material is attenuated by adding at least 0.05equivalents of a complexing agent per equivalent of hydrolysablelithium, nickel and bleached state stabilizing element in the liquidmixture.
 13. The process of claim 9 wherein the lithium source materialis a lithium salt of a coordination complex corresponding to the formula[M⁴(OR²)₄]−,[M⁵(OR²)₅]⁻, [M⁶(OR²)₆]⁻, or [L_(n)NiX¹X²X³]⁻ wherein L is aneutral mono- or polydentate Lewis base ligand, M⁴ is B, Al, Ga, or Y,M⁵ is Ti, Zr, or Hf, M⁶ is Nb or Ta, n is the number of neutral ligands,L, that are coordinated to Ni in the coordination complex, each R² isindependently hydrocarbyl, substituted hydrocarbyl, or substituted orunsubstituted hydrocarbyl silyl, and X¹, X², and X³ are independently ananionic organic or inorganic ligand.
 14. The process of claim 9 whereinthe hydrolysable source material is hydrolyzed by water generated insitu in the liquid mixture.
 15. The process of claim 14 wherein water isgenerated in situ by the addition of an acid catalyst to the liquidmixture.
 16. The process of claim 9 wherein the hydrolysis rate anddegree of hydrolysis of the hydrolysable source material is attenuatedby adding a complexing agent to the liquid mixture.
 17. The process ofclaim 16 wherein the complexing agent is a coordinating acid.
 18. Theprocess of claim 17 wherein the coordinating acid is ethoxyacetic acid.19. A process for forming a multi-layer electrochromic structure, theprocess comprising: depositing a film of a liquid mixture onto a surfaceof a substrate to form a deposited film, wherein the liquid mixturecomprises a continuous phase and a dispersed phase, the dispersed phasecomprising metal oxide particles, metal hydroxide particles, metalalkoxide particles, metal alkoxide oligomers, gels or particles, or acombination thereof having a number average size of at least 5 nm, and;treating the deposited film to form an anodic electrochromic layercomprising a nickel oxide, the anodic electrochromic layer adapted tocycle between a bleached state transmissivity of at least 70% and adarkened state transmissivity of less than 30%.
 20. The process of claim19 wherein the anodic electrochromic layer is adapted to cycle between ableached state transmissivity of at least 75% and said darkened statetransmissivity.
 21. The process of claim 19 wherein the dispersed phasecomprises a species containing lithium, nickel and/or a bleached statestabilizing element.
 22. The process of claim 21 wherein the bleachedstate stabilizing element is selected from the group consisting of Y,Ti, Zr, Hf, V, Nb, Ta, Mo, W, B, Al, Ga, In, Si, Ge, Sn, P, Sb andcombinations thereof.
 23. The process of claim 21 wherein the atomicratio of lithium to the combined amount of nickel and the bleached statestabilizing element in the liquid mixture is at least 0.4:1.
 24. Theprocess of claim 21 wherein the atomic ratio of the combined amount ofthe bleached state stabilizing element to the combined amount of nickeland the bleached state stabilizing element in the liquid mixture is inthe range of 0.025:1 to 0.8:1.